Category Archives: signals

Itinera interruptus

Question: Why are we stopped here?

I see this question a lot, with “here” referring to many various points along the alignment. Very rarely do people get on the MAX train just to sightsee where it happens to go (though I have seen tourists do this). Instead, generally people on board have places they need to be and buses they need to catch, and as a result they get anxious when a train is stopped longer than a normal platform dwell time.

The most common cause is typically waiting for other trains to clear, and frequent “hot spots” where the wait is most likely due to rail traffic include:

Steel Bridge

All roads (well, MAX lines) lead to the Steel Bridge, and as a result you can find yourself waiting to cross it since all trains go through here. And of course, if there is a bridge lift, maritime traffic takes priority over rail so you’ll also be waiting if that happens, to say nothing of the delays from trains stacking up during the lift.

train on the spanRed Line train crossing the Steel Bridge

Under normal operating conditions, a delay might happen on the span itself. A westbound Red or Blue Line train like the one pictured above will be held at signal 14 if a Green or Yellow Line train is crossing the bridge heading toward Rose Quarter. The reason for this is that the tracks cross each other:

Steel Bridge west side

This angle looking down on the western side of the bridge works well to illustrate this since the sun is reflecting off the rails making them easier to see. The two tracks coming straight down in the middle of the bottom of the picture are for Yellow and Green Line trains. The ones going off to the bottom right corner are for Red and Blue Line trains. You can see that a westbound Blue or Red train (coming in from the left track at the top of the picture) needs to cross the path of an eastbound Yellow or Green to continue into the Old Town/Chinatown platform. An eastbound Red/Blue does not have this conflict with a westbound Yellow/Green, so you won’t see those trains waiting, but westbound Reds and Blues will wait on the span until the incoming Yellow or Green is clear.

New signal 10Signal 10 at Old Town/Chinatown – the switches are set but the cars crossing in front of the train still have a green light (pre-empt signal refresher)

Similarly, if a conflicting move is in progress or switches aren’t yet set properly, trains waiting to cross the bridge eastbound will be held. This is why you may find yourself waiting at Old Town/Chinatown on a Red or Blue train – your operator is waiting for a permissive aspect on signal 10, but won’t get one if a Yellow or Green is starting to go eastbound over the bridge (and those trains can be held at signal M26) if a Red or Blue is already crossing.

On the other side of the bridge is Rose Quarter, which is complicated enough to get its own post. In short, Reds, Blues, and Greens can generally move through here without conflict (e.g. you can have a westbound Blue leaving RQ at the same time an eastbound Green comes in without any problems) but since the Yellow Line turns north here and crosses the other tracks, Yellow Line trains can only move through the Rose Quarter interlocking at the same time as other Yellow Line trains.

yellow line parallelTwo Yellow Line trains making a parallel move

So if you are sitting westbound at Rose Quarter for longer than expected and there’s no bridge lift in progress, most likely your operator is waiting for a Yellow Line to get out of the way. And on the flip side, if you’re on a Yellow Line sitting at IRQ waiting to cross the river into downtown, there’s probably a Red, Green, or Blue going through that has to clear before you can move. Trains heading off the span into Rose Quarter may be held at signal 16G if a conflicting move is in progress.

Gateway

EB from GatewayEastbound from Gateway

The fishhook (not used to catch prostitutes) is the biggest time sink at Gateway. It’s a curving stretch of single track with a 10mph speed limit used to connect Red Lines with the alignment going north on I-205 toward the airport. In the above picture, the track diverging to the right off the eastbound main is the start of the fishhook. Since Red Line trains use this to come in and out of Gateway, in this part of the alignment where the picture was taken, westbound Reds will actually be traveling in the eastbound mainline for a short distance. So if you’re on an eastbound train at Gateway not going anywhere, take a look to your right over toward the fishhook. The odds are good that an inbound Red Line got through their signals before your train’s operator selected at Gateway, and it’s making its way up the fishhook into Gateway. Your train can’t move until they’re clear.

green and red trainsRed Line coming off the fishhook as a Green Line waits in the auxiliary track

incoming greenGreen Line train heading into Gateway from Clackamas

There can also be delays for Green Lines coming in to Gateway, but since that alignment has double track, it does not present the same problems as the single track fishhook does (sometimes a brief wait at the SE Main St platform or at the intermediate signal if a Blue Line is going through here).

Downtown/Goose Hollow with Conga Lines

supervising conga line

The above picture is something of an extreme example from an evening when a switch by Beaverton TC broke and trains were backed up all through downtown. But it’s not uncommon for trains to end up forming a conga line during rush hour. In this picture, the platforms are near each other and it’s not a problem (from a safety perspective) for the trains to be that close. However, once they get to Goose Hollow, they move into ABS territory which involves much greater spacing between trains and trains traveling at higher speeds. A westbound train at Goose Hollow can’t proceed until its leader passes a signal in the tunnel prior to the Washington Park platform. You’ll hear the train waiting to proceed call this in on the radio as being “on a red at Goose” – because you can’t see into the Goose Hollow platform until you’re almost into it, trains waiting at Goose Hollow will let Control and their followers know that they’re occupying the platform, in which case the train behind can wait at Kings Hill instead of at the intersection right before the platform.

ABS Territory – Intermediate signals

If you’ve ever been on a train in ABS territory (in particular east of Hillsboro but west of Goose Hollow and east of Lloyd Center to PDX, Gateway, or Clackamas) and the train slows to a crawl between platforms, sometimes coming to a full stop before resuming normal speed, that means your operator was approaching a red ABS signal:

Red ABS diagram

This is a safety measure in high-speed travel areas. There are intermediate signals between many of the platforms, and if your leader is still between the signal in front of you and the next signal, your train will have a red light that will trip you if you try to go past it. This prevents trains from getting too close at high speeds. Passengers won’t always notice this one, because it’s generally preferable to drop your speed and creep up to the signal hoping it turns yellow before you get there instead of immediately coming to a stop when you see a red (it’s best to avoid stopping a train away from a platform when possible). But if you get all the way up to the signal and it’s still red, your operator will stop the train until the signal turns yellow. This informs the operator that the train in front of them is now far enough ahead that it is safe to proceed.

Waiting for Relief

Aside from areas where trains are stopped while waiting for other trains to clear, I’ve also seen people ask why trains have to switch operators while still in service. Although there are some tripper trains that will just go yard to yard or make one round trip and then go back to the yard, most trains are in service all day. So each line has relief points built in where one operator’s shift ends and another’s begins. For the Red Line, this is Beaverton TC and as a result you won’t notice any delay because the relief will happen while the train is on layover. For the Blue Line, reliefs are generally at either Elmonica or Ruby Junction, though there are a couple of runs that are relieved at Beaverton TC and Gateway. For the Yellow and Green Lines, all reliefs are at Gateway.

I’ve mentioned this before, but a relief operator will call into Control with their train number and the word “relief”. After Control acknowledges the call, the relief operator responds with their badge number and lets the controller know if he or she is signed in and has train orders. The controller will let the operator know if there’s anything important going on they should know about (sporting event, service disruption, etc).

Generally speaking this process does not take long so these aren’t long delays, but more importantly, there is time built into the schedule for reliefs:

Relief time

This is an excerpt from a paddle, or rail schedule. The plus sign after the time means 30 seconds. So to read this, the train arrives into Gateway heading toward PSU at 1:28:30pm But that train is not scheduled to depart until 1:30:30pm, giving the relief operator two minutes to call Control.

This is one of those little things I wish TriMet would publicize – I know passengers get frustrated because from their perspective, they’re sitting at a station for 2 minutes not doing anything, and now they think they’re late. However, they’re actually not late at all, the schedule is designed for the relief and the train will be leaving when it is supposed to.

Other Delays

These were the main reasons why a train will be stopped for longer than normal platform dwell service. Of course, countless things could come up in a day that will cause delays and result in trains holding – police activity, medical emergencies, a train or alignment malfunction, a car in the right of way (since that seems to happen about once a week). In those instances, your operator will likely be doing what they can to keep you posted as information about the delay and when things will be moving again becomes available. However, if you’ve been sitting for 3 or 4 minutes without any explanation, it’s ok to use the emergency intercom and ask what’s going on – operators are trained to keep passengers informed (even a “Ladies and gentlemen we’ve been asked to hold here, I will let you know when we will be moving again” when Control doesn’t give an explanation for the hold is better than not saying anything at all to passengers).

How you can help prevent delays

smokeyYes, you.

Given the delays that can happen around the Steel Bridge, Rose Quarter, and Gateway if trains aren’t on schedule, it’s important for passengers to do their part and not contribute to any delays. Much like how a green light will eventually turn yellow and then red when you’re driving, a train won’t have a permissive signal indefinitely. If you’re downtown, on Interstate, or on Burnside, you can see the signal start to time out when it does this:

Flashing white vertical

A train can’t enter the intersection when a pre-empt is displaying this aspect because it won’t clear the intersection before cross traffic gets a green light. ABS and ABS-pre-empt combination signals will go back to red when they time out.

Although you might think it’s polite to hold the door open for someone running for the train or trying to buy a ticket, what you are actually doing is making the operator miss their signal because it timed out and now they have to wait again. This can mean your train will be late getting to one of those traffic-heavy areas, and what you thought would just be a short delay to help a late-runner has turned into a 5 minute or more delay. On the transit mall, causing a train to miss a signal not only delays your train but buses as well.

And yes, it bears repeating, this is also why an operator is not likely to reopen the doors if the train is stopped with the doors closed even if you come running up to it. Once an operator calls the signal, it’s time to be ready to move as soon as the signal is permissive. This helps the train stay on schedule and minimizes the likelihood of interrupting everyone’s trip by needing to stop and wait further down the alignment.

Rose Quarter, revisited

I thought I’d do a post on the operational side of what’s going on around Rose Quarter after an out of control car careened into some signaling equipment last week, since the only side the public sees is pretty much just the loss of Transit Tracker and maybe noticing trains stopping more near Rose Quarter. A helpful primer on this would be the original post about Rose Quarter signals just to familiarize yourself with how this area works under normal operating conditions.

One of TriMet’s photos of the scene. Only one car was involved; the blue car in the background is a supervisor’s car that was narrowly missed by everything

The Impact’s Impact on Transit Tracker

Preface: I am not a signal tech and have nothing to do with Transit Tracker, so if anyone who has a better handle on this than me wants to step in and fill in the gaps/correct me if I’m wrong, please, by all means do so. For all the folks reading the news about this and subsequently wondering why Transit Tracker was routed through here or “stored” in this box, this wasn’t a mythical box that Transit Tracker lived in any more than your computer is a mythical box that the internet lives in. Transit Tracker for passengers is more of a nice little byproduct of what this box (and other signal relay boxes like it) did, not its primary purpose. To the best of my understanding, while Transit Tracker for bus is GPS-based (and therefore it was not affected), Transit Tracker for rail has been based on what circuit the train is in. The crash affected power to all of the intersections between Rose Quarter and OCC, and I know that’s affected the signals but I’m not sure the extent to which circuit detection was affected, but because Transit Tracker isn’t working I’m assuming that it was impacted. This is a centrally located section of the alignment that I am guessing is not getting standard data on train positioning, so the Transit Tracker method of locating trains to predict their arrival isn’t functional. Since ALL trains pass between these two platforms (remember that Yellow and Green are the same trains) all lines are affected.

I’m not above criticizing TriMet when I think they make bad decisions or plan things poorly, but I think this was unfortunately a situation in which there was no right thing that TriMet could have done that would have made everyone happy:

  • Some people are saying that sensitive equipment shouldn’t have been in a high-risk area. As far as I know, given that Rose Quarter was part of the original alignment (called Coliseum there), that box or something like it has probably been there since the mid 80s. But as a conservative estimate, we know that the equipment was 16 years old, so let’s say it’s been there since the mid 90s at the latest. This is the first time a car has come careening off of I-5 doing about 80mph ass over teakettle onto the platform, so I’m going to say that this isn’t really a high-risk area, it was the site of a freak accident. I have not heard of any other crashes in that area coming anywhere near close to where the box had been. Besides, it was tied to the alignment in that area – where else are you going to put it?
  • The equipment in the box was so old that replacement parts aren’t available. Fine, it’s old, but you know what? It worked. There’s probably a fair amount of infrastructure in use right now that’s equally old and not easily replaced (I think the fact that TriMet spokesperson Roberta Alstadt said that the delay in replacing it is due to finding something that can communicate with the rest of the system pretty much says that the rest of it, if it fails, can’t be easily replaced either). And just imagine the fits that people would throw if TriMet were to announce they were spending millions to retrofit rail equipment that would make Transit Tracker more reliable or fit all the rail cars with GPS as bus routes are being sliced and 20+ year old buses are on the road. Would replacing this before this incident happened have been the best use of TriMet’s limited money? How about putting GPS on the trains when the circuit location system works? Setting up bollards everywhere a car might fly into something? Yeah, it’d be nice to replace all of the old equipment but I think there are higher priorities for TriMet when it comes to replacing old equipment (e.g. BUSES) than this would have been.

Sure, the loss of Transit Tracker is probably annoying to commuters, but trains are still able to safely pass through this area with minimal delay. If anything, I think this shows a strength of rail in that while a fixed right of way is never going to be as flexible as a bus, there are still workarounds to even major issues like this to keep things moving. So now on to what’s going on here operationally:

Special Instruction 79

Those of you following along at home on the radio have probably heard a lot of trains calling in either from OCC westbound or Rose Quarter eastbound to follow special instruction (SI) 79. Remember that a special instruction is a temporary modification to operational rules that can be in effect for up to a year, versus a train order which expires after 24 hours.

The operationally relevant part of SI 79

And now, in English.

Eastbound trains must stop and call Control from Rose Quarter. For most trains, this will be from the eastbound main platform and signal 18G, though the SI is set up to allow for eastbound moves from the special events track, westbound main or trolley barn as well (for a review of those signals, refer to the previous post on Rose Quarter). Since the signals cannot be called normally through train-to-wayside communication to get a proper to proceed, the automatic train stop (ATS) magnet in the platform will be active and the train will be tripped if the operator tried to go.

ATS trip and bypass counter inside cab of train

Inside each train cab is an ATS counter like the one pictured, which records the number of times that cab was active (i.e., had an operator keyed in and moving forward) and tripped an ATS magnet as well as the number of times an operator has bypassed an ATS magnet. When you bypass a magnet (also referred to as “key-by”), you have 23 seconds to get past it without it stopping your train. Control keeps a record of the totals in these counters for each train car and cab – it prevents an operator from selectively bypassing an ATS magnet or from tripping and continuing without calling it in. You never bypass a magnet without direct authorization from Control first.

So the operator will tell the controller what car and cab they’re in, and what their new bypass number will be. When they have a fresh parallel walk sign on 1st Ave, they will bypass the magnet so they can proceed forward, ensuring that the switch (topmost one in that picture) is not set against the movement since this area does not currently have signal protection, and also ensure that the intersection is clear of any pedestrian or vehicle traffic. The instructions to stop at 2nd and 3rd and then proceed when safe are slightly different from the standard instructions to SOP an intersection, due to the lack of power at these intersections which means they aren’t displaying parallel green lights. Once into the OCC platform, normal operations can resume as points east were not affected by the crash.

Call board at OCC westbound.
There’s one of these at Rose Quarter eastbound as well.

Westbound the procedure is fairly similar. At the OCC platform, operators will call Control and report their car, cab, and new bypass number. The ATS magnet in this direction is up closer to 2nd Ave by signal 18A.

After getting permission from Control to proceed, trains can proceed when safe through 3rd Ave, which is is street immediately in front of OCC when facing west. They must then stop at 2nd to bypass the ATS at signal 18A, ensuring that those switches in the above picture are properly set for a move into the westbound track (or the special events track if directed there). Once at 1st Ave, the operator will make sure that Rose Quarter is clear and wait for a fresh parallel walk sign before continuing into the Rose Quarter platform and then proceeding as normal to all points west.

This special instruction will be in effect until everything through here is fixed, presumably over the next few weeks. Since all of the steps are packaged into the SI, it cuts down on the amount of radio transmissions for everyone – operators don’t have to call in for permission at each intersection after the initial call to Control, and controllers can grant permission to “follow SI 79″ without needing to say all of the steps each time a train goes through here.

Window washer rope around pantograph (Photo by Jason McHuff, more here)

Now consider that the RQ-OCC issues were still going on yesterday and SI 79 was in effect when the window washer’s rope took out Red & Blue Line service downtown (which was pointed out to me was once again the unfortunate car 235) and a semi truck hit a Yellow Line train on Interstate, causing trains to be turned around at 7th or Jeld Wen or Jackson or where available.

Semi vs MAX, picture from Twitter

Yes, there were delayed trains and crushed loads for commuters, but the amount of effort required to keep anything moving at all when that many things go wrong is pretty phenomenal. I do think that there are a number of areas that TriMet needs to improve, such as getting word out to passengers in a more timely manner, not pulling in-service buses out in order to bus bridge (or at least not pulling as many – it leaves bus passengers stranded, puts a lot of strain on the buses left in service). But I still think that it’s good for the public to be able to see “behind the curtain”, so to speak, to get an idea of what’s involved on the back end to get people to their destinations when things go wrong.

Repeater signals

Another post about signals… this time the rail kind. I thought about this while writing the last post, because this is sort of like a literal signal boost.

There are two signals on the Banfield between Lloyd Center and Hollywood TC that function differently from the rest of the signals on the alignment. These signals (34R and 36R) are repeater signals. They “repeat”, or display the same aspects, as ABS signals 34 (eastbound) and 36 (westbound) respectively, but are positioned slightly ahead of the signals they repeat because those signals are around a curve.

34 R (eastbound), which is repeating the aspect displayed on…

…Signal 34

Signal 36R does the same thing for signal 36, which is seen going westbound. I don’t have a picture of signal 36, but here’s its repeater signal:

Signal 36R (westbound). Signal 36 is located around the curve ahead, back-to-back with signal 34.

The speed limit through here is 45 mph, so due to the limited visibility with signals 34 and 36 being on a curve, it would be difficult to stop a train in time if those signals were red. The repeaters give advanced notice of what aspect those two signals are displaying so operators can act accordingly and stop if necessary.

Notice how there are no ATS magnets near the repeater signals, but you can see the ATS magnet (it looks like a small box between the rails) in the picture for signal 34. Going through a red on 34R or 36R won’t automatically bring your train to a stop, however, you still treat like all other red signals and stop your train prior to the repeater if it’s red. And if you run a red on a repeater signal and then trip the signal after it, I believe that counts as two rule violations for going through two red signals (which I’ve never done..).

Rose Quarter

For reader Matt, who had asked about signals at Rose Quarter some 6 months ago and I’m finally writing about it. In other words, it’s a good thing “Professional Blogger / Fielder of Questions” isn’t what TriMet hired me to do.

The Rose Quarter interlocking is very complex (I’ve heard it’s one of the most complex in the country, but I don’t really have much of a basis for comparison). I’d wager it’s probably also one of the busiest, with trains passing through every few minutes. The complexity of this interlocking’s design allows for a lot of flexibility for trains in the event of a bridge lift or other reroutes.

For simplicity, in this post RQ refers to the Rose Quarter platform used by Blue, Red, and Green Line trains. IRQ refers to the Interstate Rose Quarter platform used by Yellow Line trains.

First, the whole thing from above:

As always, click for larger

Rose Quarter Platform

Starting with the signals associated with the Rose Quarter platform.

Looking west into RQ from OCC

Coming into Rose Quarter from the east (Oregon Convention Center platform), the first signals you encounter are 18A and 18B. 18A protects switches 13A, 11C, and 11D, and will remain red with an active ATS magnet if any of those switches are not aligned to move west or if there is a conflicting move in progress (e.g. a vintage trolley coming in or out of the trolley barn). 18B gives you a choice of routes between the special events track which is the middle platform, the westbound mainline track which is located to the right of the special events track, or the trolley barn.

Now in the RQ platform, looking westbound first:

16B and 16C can display identical aspects for identical routes (remember, it’s not where you are, it’s where you’re going) – the only difference is that 16B is for trains heading west from the special events track and 16C is for trains in the westbound main. A white vertical will send you toward the Steel Bridge; a red over white vertical will send you toward IRQ (Yellow Line). These signals will stay red if the bridge span is unlocked for a lift, or if there is a conflicting move in progress with the Yellow Line.

And then east from Rose Quarter:

18D, which is used by vintage trolleys leaving the barn – a white vertical to continue to the eastbound mainline; a red over white vertical for a reverse move onto the westbound mainline.

18E and 18F (similar to 16B and 16C) can display identical aspects for identical routes, with 18E used by trains in the westbound main and 18F used by trains in the special events track. A white vertical will send trains east on the eastbound mainline; a red over white vertical will send trains east on the westbound mainline.

18G is the signal for eastbound trains in the eastbound mainline at RQ – no choice of routes available here. Memory trick for memorizing signal numbers (though I don’t think they do that anymore in rail training) – “G” for Gresham, and signal 18G will get you there.

Then away from the Rose Quarter platform itself…

Interstate Rose Quarter Platform

16E at the IRQ platform. A white vertical on 16E will send Yellow Line trains over the Steel Bridge; a red over white vertical will send them into Rose Quarter. This is how Yellow Line trains can get from Expo to the Ruby yard at the end of the day. Also, when a Yellow Line train operator forgets to change the route code in their trailing cab from Clackamas’s 12 to Jackson’s 50, they get a red over white vertical here.

Then at the other end of IRQ are N2A (for trains heading north from the southbound track) and N2B (for trains heading north from the northbound track) – like Rose Quarter, IRQ is also set up to allow turnbacks in the event of a bridge lift. A lunar on these signals will send trains on the northbound mainline; a red over lunar into the Broadway Siding - you may have been on a train in the morning where it stops at IRQ, kicks everyone off, but then appears to continue north. It only goes as far as the Broadway Siding before turning around and going back west over the Steel Bridge. (Linked video was not filmed, narrated, or posted by me and does not feature me. Linked video is also old, Train 6 hasn’t done that for a while, but 33 does it currently)

Coming off the Steel Bridge

16G will display a lunar for trains heading into RQ (Blue, Red, and Green Line trains), and a red over lunar for trains heading into IRQ (Yellow Line trains).

Assorted pics of and through the interlocking

Both heading westbound toward the Steel Bridge from Rose Quarter

Can diverge to or from IRQ

You can see how you can get from either track at IRQ to RQ or the Steel Bridge

Switches and crossovers

I also have this video which I’d originally posted a few months ago, showing a view from the cab from 1st and Morrison to Rose Quarter. This was a Red Line train, so we got a lunar on 16G and went through the interlocking at the same time as another Red Line Train.

Making a parallel move with a westbound train

Given the design of Rose Quarter, what’s ideal for train movement are parallel moves, where trains can move in opposite directions at the same time. Scheduling trains to do this reduces the need to wait for other trains (e.g. sitting at RQ waiting because a Yellow Line is going through, so the switches are set against you) as well as reducing the impact that trains moving through the intersection has on auto/bike/pedestrian traffic.

Yellow Line trains making a parallel move

Train numbers, route codes, and more with signals

Question: How does a train know where to go?

This question comes up a lot, and although I’ve answered it in comments or emails or Twitter, I’ve never given it its own post. But a lot of people have asked, for example, if a train is eastbound at Gateway, what do you do to it to send it to Gresham vs the airport vs Clackamas? Sure you call the signal but how do you get the right aspect(s) to come up for where you want to go? It’s not like the trains have a steering wheel.

(Actually it’s kind of fun to let kids see the cab of a train at the end of the line and ask them where the steering wheel is. It stumps their parents too!)

It’s a trick question.  Here’s the “steering wheel” of a MAX train:

Route code (and train number, which is blurred out, you don’t need to know what train number this was, but in following safety procedures, I assure you the train was stopped at the end of the line – not only was it not moving it wasn’t even keyed in), Type 2 thumbwheels

In the cab of each train is a place to set the train number (under normal operating conditions, this won’t change over the course of the day) and also the route code. The train number is the train’s identifier, and it matches the number visible in the window box – for example, the train in the old header picture of this blog was train 40; the train in the old background image was 71. If Control wants you, they’ll call your train number over the radio. If you need something, you begin a radio call to Control by stating your train number.

You can tell what yard a train is from (though not necessarily what yard the operator is from due to reliefs) and what color its route is from the train number. Trains 1-15 are Blue originating out of Ruby, 20-38 are Blue out of Elmonica, 40-53 are Red out of Elmonica, 60-74 are Yellow/Green out of Ruby, and the Mall Shuttle had been train 89 out of Ruby. Trains not regularly scheduled, such as those used for testing or burn-in get numbers in the 90s. There are some exceptions to this breakdown, like train 10 is Blue most of the day but becomes Red at night, 43 begins its day going from Elmo to PDX to Hatfield before becoming a regular Red Line, but this is all pretty much just trivia for passengers anyway, it’s not like I’m going to quiz you on this later.

The route code is what tells the train where to go from its current location. Every possible destination on the alignment that can be reached via power switches has a route code assigned to it – not just the ends of each line, but also the yards, sidings, pocket tracks, etc.

Sign at Galleria with 11th Ave route code

In the first picture in this post, a route code of 50 will get a train to either track 1 or 3 in the Jackson turnaround by PSU, whichever is open. Every time an operator places a train-to-wayside call over a call loop, the switches will be set to move the train toward the destination set as the route code, and the corresponding signals will be displayed. Operators are responsible for ensuring the route code is correct for where the train is supposed to go. For Blue and Red line trains, this is pretty easy – the cab that leads going east will be set for Gresham or PDX, and the cab that leads west will be set for Hillsboro or BTC so it does not need to be adjusted frequently (well, it’s easy as long as Red line operators don’t forget to change the route code from the BTC pocket track on the last trip and end up in there when they need to keep going west…).

Yellow/Green line trains are a little trickier. For trains leaving Ruby to service those lines, depending on which run it is the route code will be set for Expo, the Jackson turnaround, or the Gateway auxiliary track (where the operator will swap cabs and take the train to Clackamas). Then to change color at Jackson, the operator will leave Clackamas (for example) with the route code for the Jackson turnaround, and then once there will set the route code for Expo. When leaving Expo in the other cab, they’ll set the route code for Jackson, and then once in the Jackson turnaround, they’ll change the route code for Clackamas. Potential errors can happen if an operator forgets to change the route code from 50 when leaving Jackson (if that happens, the train will head back south to PSU from Union Station instead of crossing the Steel Bridge) or forgetting to set the route code for Jackson from the end of the line (so for example, heading toward Clackamas from Interstate Rose Quarter instead of over the Steel Bridge).

Signal aspect review

Signals will reflect what route code is in your thumbwheel. First, here’s a quick overview  of signal aspects (for more information, I’ve written a lot about signals already)

A red aspect – STOP

A yellow aspect – clear for one ABS block (that is, the distance to the next ABS signal) on the primary route

A green aspect – clear for two ABS blocks on the primary route

A lunar aspect – proceed with caution, tracks may not be clear (your switches are set but no indication of train occupancy ahead)

The number of aspects that are lit indicates which route you’ll be going on (one aspect = primary route, or “A” route. Two aspects = secondary route or “B” route. Three aspects = tertiary “C” route, etc). As an operator, when you’re looking at a signal that can display more than one route, you need to know which of those routes corresponds with the route code you have in your thumbwheel.

Back when I was first learning the signals, one of the most confusing parts for me was confounding signal aspects with switch positions, in part because yellow over green signals are referred to as “advanced diverging” and red over yellow are referred to as “diverging” – so that means when you see one of those signals, you can expect switches to be set diverging, right? Well, not necessarily…

For example, at the ends of the lines (here into Cleveland Ave from Gresham TC) a single yellow aspect will actually put you over diverging switches into Cleveland, but a red over yellow is a straight shot in. A signal with two aspects means that you’re diverging from the primary route, but not necessarily diverging over switches – it could be that the primary route itself diverges over switches but the secondary route goes straight. I had been thinking about the ABS signals in terms of switches, not routes, and that was a stumbling block for me. A permissive signal indicates that your switches are set for whatever your route code is, but you have to know if that means they’re diverging or normal.

Same with this red over white vertical on W1760 at Hatfield – it’s a secondary route (2 aspects), but this train will be going straight in, not diverging over the switches. Sorry for the blurry picture but it’s the only one I have.. I either need to go out there and get a clearer one or get someone to do that for me.

It’s not where you are, it’s where you’re going

So keeping in mind that an ABS (or ABS-pre-empt combination) signal displays your route, here’s an example of what it looks like when you can call the same route from two different locations. Take a look at these signals:

Signal 76: Red over red over green
Clear for 2 ABS blocks to Clackamas TC

Signal 78: Red over red over yellow
Clear for 1 ABS block to Clackamas TC

Both trains that called these are facing east at Gateway – the one looking at signal 76 is in the eastbound main; the one looking at signal 78 is in the pocket track. Both have a route code set for Clackamas TC. And from both tracks, that’s the “C” route / 3rd route / tertiary route, which is why both signals are showing 3 aspects. These aspects are almost functionally identical (the yellow on 78 just means that this train’s leader is only one ABS block ahead of them, otherwise that would’ve been a green) even though the train observing signal 78 has two more sets of switches to diverge over to get to the eastbound main to get to Clackamas.

Gateway from above, click for larger

The platforms are in the bottom of the picture – from left to right, that’s the westbound mainline, pocket track, and eastbound mainline. Notice that to get over to the eastbound main alignment (which, out of range of the top of the picture, diverges off to Clackamas) a train in the pocket track has to pass over the switches that could otherwise bring it to the auxiliary track, and then over another set of switches to join the eastbound main. Yet its signal aspect at Gateway to get to Clackamas is identical to what a train in the eastbound mainline would get, even though the train in the eastbound mainline doesn’t have to worry about those switches.

Where a train is starting from doesn’t matter – where it’s heading is what will be displayed on the signal.

Lunar on signal 78, eastbound from Gateway pocket track

Lunar on signal 76, eastbound main at Gateway

Similarly, a train with a route code for Cleveland (or the Ruby Yard) going east from the pocket track will get a single lunar aspect on signal 78, just like how a Blue Line train heading east at Gateway will have a lunar on signal 76, even though a train starting from the pocket track has to diverge over switches to get there. The signal indicates that the switches are set for the route code in  your thumbwheel, but you have to know if that means the switches are set normal or diverging (because you do NOT take a train at a high speed over these diverging switches!)

Here’s another example, eastbound at Beaverton Transit Center.

Signal W760 is for a train in the pocket track (which is typically a Red Line), and W754 is the signal for the eastbound main. A train heading east from the pocket track will have to diverge over switches to get into the eastbound main, yet the ABS signal will show a single aspect indicating the primary “A” route. It doesn’t matter where the train is at, it matters where it’s going – and for trains in either track here, the only place to go is the eastbound main (primary route), therefore both signals have a single head that can only display a single aspect. There is no choice of route from either track, even though you will be diverging into the main eastbound track if you are leaving the pocket track.

W556 at Sunset, for a Red Line train heading to the BTC pocket track

On the other hand, if you’re headed west into BTC, you do have a choice of two routes (along the westbound mainline or into the pocket track), which is why signal W556 at Sunset and the intermediate signals leading into BTC (W616 and W716) can all display one or two aspects for a primary or secondary route. The signals will indicate that the switches are set for whichever of those route codes you have in your thumbwheel.

You know, I don’t know how to end posts. I feel like I should assign a 2-page essay on the importance of ensuring you have the right route code in your thumbwheel and how that relates to ABS signal aspects. Show your work.