Category Archives: switches

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.

Conga line

Westbound trains were delayed Friday due to a switch issue by Beaverton Transit Center. There are three power switches to get into or out of the pocket track from the east, and the one farthest to the left in that picture was not throwing properly, so rail supervisors were on scene to manually throw the switch and direct trains safely through the area. I was off work and downtown when all of this was going on and from what I could see the operators were doing everything they could – getting on the PA to announce the reason for the delay and apologize for the inconvenience. Surprisingly, given how backed up everything was, no official service alert was released. Of course, people weren’t happy about the delay or being stopped for a while only to proceed up to the next platform and then stop again.

Not a great time to be operating, but a good topic for blogging…

Things were very backed up – this conga line of trains at every platform on Morrison is the result of that issue way out by BTC. If you look closely, you can see there is a Type 4 up at Galleria, then another train at Pioneer, then this train next to me at the Mall/5th platform, and another train behind it at 3rd/Morrison.

A common complaint I was hearing was that passengers didn’t understand why the trains were stopped where they were – can’t they keep moving, even if slowly? There are a couple of reasons why trains were holding where they were. One: stopping away from platforms is something to avoid whenever possible. Passengers can get a little agitated and uncomfortable being on a train that isn’t moving, and it’s dangerous for them to pull the emergency door release to leave the train away from a platform – first because that can likely put them in the path of a train coming in the other direction or vehicle traffic (depending on your location), and second because even the low-floor train cars have a drop to the ground if you’re not at a platform. So it’s preferable for stopped trains to hold at platforms with their doors open or on release which allows people to leave the train safely.

Two: west of Goose Hollow is ABS territory. To review:

ABS diagramDiagram of ABS signals

The direction of travel is from left to right. On the top part of the image, a green signal indicates that there are two open blocks (that is, the space between the signal in front of you and the signal after that one, AND the space between that signal and the one after it both are clear of trains). In the middle part of the image, the yellow signal indicates that there is one open block between  you and the train in front of you. The bottom part with a red signal indicates that the train in front of you is in that block. If the block in front of you is occupied, you CANNOT proceed into it. The block system and associated ATS magnets work to keep the trains spaced at a safe distance and prevent collisions.

So even though there appears to be more than adequate space for all of these trains to have rolled through downtown and waited behind each other on the alignment just east of Beaverton TC to proceed through, multiple trains cannot safely occupy the same ABS block. Additionally, since it’s safest to have the trains holding at platforms whenever possible, it’s better to have the trains stacked up here than at each ABS signal along the west side where there is no safe way for people to exit the train if they’re not at a platform.

Conga line of trains proceeding through downtown, monitored by supervisors

Rail and switch review

I found a picture that I’d taken a while ago of switches near Rose Quarter- it probably should have gone in my last post but I’ll put it here and make this a review post about switches and rail types. First: rail types.

Borrowed picture which shows cross-sections of both types of rail used on the MAX alignment: t-rail on the left, girder rail on the right. Girder rail is used in lower speed areas (CBD/downtown & Holladay, Washington Street in Hillsboro), and t-rail is used everywhere else. Along Interstate, the t-rail is embedded in pavement so it looks similar to girder rail. This picture shows the embedded rail on Interstate along with the crossover switches that are not embedded.

Here is the picture of Rose Quarter, where girder rail is what’s used:

Switches, looking east from the westbound platform at Rose Quarter

This picture shows the different routing options available on the eastern side of the Rose Quarter platform. The nearest track is the westbound mainline, the one diverging off to the left side of the picture leads to the trolley barn, the one that’s actually a straight route from the westbound mainline is the special events track, and the far track is the eastbound mainline. In this type of rail, the only way to tell how switches are set is by observing the switch points – while the ABS/combination signals associated with these switches tell you what the route is, it’s still necessary to observe that the switches are set properly.

West Ladder, Elmonica Yard

Compare the switches at Rose Quarter to these in the Elmo yard, facing the storage tracks. These t-rail switches are power switches, meaning they can be thrown remotely from the cab of a train, and they have switch indicators (green for switches set normal, yellow for switches set diverging – remember manual switches in t-rail use targets with the same colors). You can see how the color of the indicator matches how the switch points are aligned. Girder rail switches don’t have indicators like these to make it easier to tell how the switch points are set, but even with indicators it’s still always necessary to observe switch points – an indicator can be wrong, but switch points never are.

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.

Improving transit speed part 2 – Holladay

A continuation of the last improving transit speed post, which is building off of the discussion over at Portland Transport, and now specifically focusing on people’s suggestions for speeding up travel time along NE Holladay. I hope this provides something of an operational perspective as to why some things are the way they are and that might prove to be a hindrance in redesigning platform placement. These are not necessarily insurmountable obstacles, but are, at the very least, obstacles that prevent any of the suggestions from the Portland Transport post from being enacted immediately.

NE 7th Ave and OCC

Courtesy of Portland Transport, here are weekday passenger counts for eastbound stops on Holladay during fall 2010 (westbound not listed but they’re pretty comparable):

Stop—————–Ons—–Offs
Rose Quarter—–1,207—1,035
Convention Ctr.—–433—–595
NE 7th—————396—–764
Lloyd Center——1,000—1,830

Given those lower passenger counts compared to RQ and Lloyd Center, many people have put forth the argument that Convention Center and NE 7th could be closed to speed up travel time on Holladay without severe impact to passengers.

Not permanently…

However, both of those platforms serve an important purpose on Holladay – not so much for passenger loading, but rather as a necessity to travel along this section of the alignment. The short explanation is that those platforms are needed to call signals/switches on Holladay. The long explanation: keep reading.

For one thing, trains at all stops along Holladay need to call the pre-empt signals to proceed, which will then cascade into the next platform. But OCC & NE 7th have an additional complication. The alignment on Holladay from just past Rose Quarter to just before Lloyd Center is between two sets of switches. On the west (click for map), there’s a crossover as well as switches to diverge into the special events track, westbound main, or trolley barn at Rose Quarter. On the eastern side, there are switches to diverge a train into (or out of) the Doubletree Siding. Going back to my earlier posts on signal types, since all of these switches are in pre-empt territory, they are associated with ABS/pre-empt combination signals and are protected by ATS magnets.

Let’s start with the switches into the Doubletree Siding on the eastern side.

NE 7th Ave

Looking east from NE 7th

The above picture (click for larger) shows what an eastbound train at NE 7th sees. Of interest is combination signal 20A immediately prior to the Lloyd Center platform. The zoom lens makes it look closer than it really is – a better perspective (though not as clear of a photo) is this old picture from when NE 7th was where trains would switch radio channels to Main 1 or Main 3. In that linked photo, 20A is the red light at NE 11th.

In this above photo, you can see that the intersection at 9th is has a permissive white vertical pre-empt. Now look down to NE 11th at the combination signal 20A, which is displaying a yellow horizontal. This informs the operator of an eastbound train at 7th that the power switch that can diverge a train into the Doubletree Siding is aligned to continue east, but 11th is not pre-empted yet. 20A will time out back to a red after a minute, which reactivates the magnet until the next train calls it.

Approaching Lloyd Center, eastbound.
ATS magnet visible in foreground, white vertical on 20A in background.

When 20A is red, that ATS magnet will stop an eastbound train before it gets to the intersection at NE 11th. Therefore, 20A must be called by a train before it can proceed through 11th into the Lloyd Center platform, but it needs a place to call 20A from. Rolling calls, or in other words, pressing the call button as you move over a call loop without stopping, are a poor practice. Trains should be at a complete stop over a call loop to call a signal, so there needs to be some place for a train to stop prior to NE 11th to call 20A, and that purpose is served by the NE 7th platform. When placing the call at 7th, rail operators will look down to 20A from there and make sure it drops from a red before proceeding.

The NE 7th platform is needed for trains to go east to ensure that the switches for Doubletree are properly set, so 7th doesn’t work as a stop that can be closed or skipped since a train will have to stop there anyway to call 20A. (Plus 710 NE Holladay right by the platform at NE 7th is a TriMet building, so it’s unlikely that front-door MAX service is going to go away from there.)

Then over at Oregon Convention Center…

Oregon Convention Center (OCC)

West from Convention Center

Looking at OCC on the western side of the Holladay alignment, there are two combination signals that affect train movement from OCC to into Rose Quarter: 18A and 18B.

Signal 18A is located on the corner of NE Holladay & 2nd for westbound trains. It is associated with switches 13A, 11C, and 11D and the ATS magnet (visible in the above picture as the little yellow square) on the opposite corner of NE 2nd. If any of those switches are not properly set for a westbound move from OCC or if there is a conflicting move in progress – for example, a vintage trolley coming out of the trolley barn or turnbacks like last weekend’s streetcar work, 18A will remain red and a westbound train will be tripped at the ATS magnet. To proceed through here, 18A needs to be called by westbound trains from a platform (remember, no rolling calls), which is why OCC is needed.

West from OCC, 18B visible (displaying a red aspect, click for larger and look on the Rose Quarter platform)

Way down there by the Rose Quarter special events platform is signal 18B, an ABS/pre-empt combination signal that routes a train into the westbound main (click for a more up-close picture of 18B), the special events track, or the trolley barn. Like 18A, 18B is called by westbound trains from OCC, and both need to drop from reds before a train can continue west into Rose Quarter. 18B doesn’t have an ATS magnet of its own (the magnet at 2nd for signal 18A will stop a train before it gets near 18B) but this signal is still necessary for route selection. Both 18A and 18B will time out back to reds and will need to be called by the next westbound train, ensuring that the switches are properly set and there are no conflicting moves by other trains. As a result, OCC is another platform that can’t be skipped or closed because westbound trains need a platform to call 18A and 18B from. Similar to NE 7th, since trains have to stop here anyway to call the signals, they may as well service the platform.

White vertical on 18A, yellow horizontal on 18B

So can either of these stops be closed, moved, etc? Not easily.. NE 7th eastbound and OCC westbound are currently necessary to call their respective ABS/pre-empt combination signals to ensure switch alignment/no conflicting moves by other trains. And while their corresponding westbound and eastbound platforms don’t have combination signals, operators will still call for pre-empt signals to proceed from there. At present, I don’t really see a way to avoid stopping at both of these platforms despite the relatively low passenger on- and off-boarding at these locations. This isn’t to say that it can’t ever be done, but I don’t think skipping either of those platforms can be done as an immediate fix.