Monthly Archives: March 2011

Manual blocks and reverse traffic

I recently was asked some questions about

Manual blocks

(and this post got long… you might want to go make a nice sandwich or something for yourself before settling in to this one)

When train movement on one track is not available, a manual block is used to move trains on the adjacent track. This could happen because of planned maintenance, or it could be done in the event of an accident/emergency situation. In a manual block, Control directs train movement in both directions on the track that is in service. Manual blocks will have associated train orders.

You’ve done the equivalent of a manual block in your car before if you’ve gone through road construction where only one lane is open. For cars in that setting, there’s a flagger at each end of the construction area that lets a number of cars through and holds oncoming traffic from entering the single lane, and then they switch to let cars from the other direction go through. A manual block for trains is essentially the same idea – Controllers and supervisors coordinate to govern train movement into a manual block, alternating between trains running normal traffic (e.g. east in the eastbound) and others running reverse traffic (west in the eastbound).

Reverse traffic

Borrowed photo. This is not a manual block, but it shows a train running reverse (here east in the westbound at Willow Creek)

Running reverse traffic is not the same thing as backing a train up. An operator backing a train up (such as in the case of uncoupling a train car) can’t see in the direction that the train is moving – this is why backing a train up is almost never done. When an operator is running reverse traffic, they face in the same direction as the train’s movement, but that movement is in the opposite direction of what the track they’re on is typically used for.

There are a number of rules that govern running reverse traffic. First, it’s always done at restricted speed (the lesser of 20mph or the posted speed and always at a speed that the operator can stop in half their sight distance) whether or not it’s part of a manual block, unless you’re in the tunnel. Because the tunnel is signalized in both directions, trains running reverse can operate at the posted speed limits which are about the same as normal speed limits, though trains going west in the eastbound bore will exit the tunnel much slower than normal traffic because they will be diverging into the west portal pocket track. Other areas of the alignment that are signalized in both directions are already single track, e.g. the “fishhook” for the Red Line at Gateway, so travel in both directions is normal.

While running reverse, operators will also have to stop and observe every set of switch points to ensure they are properly aligned. In ABS territory, running reverse traffic is where dwarf signals come into play – they protect mainline power switches while running reverse traffic. In other words, the ATS magnets associated with the dwarf signals are active for trains going the “wrong way”. Operators will have to key-by these signals (this is done from the operating console in the train cab) after calling Control. This gives the operator 23 seconds to move the train past the ATS magnet without tripping.

On Burnside, operators running reverse traffic will have to SOP the intersections since the mass detectors are only for normal traffic. If the reverse running on Burnside is part of a manual block, the train orders associated with the manual block will include instructions to SOP intersections within the block. So operators will not need to call Control for permission at those intersections, but otherwise the process to SOP them is the same – stop, wait for fresh parallel green and walk signal and red left turn signal, sound horn warning, and proceed when safe.

You may have seen these stop signs at gated intersections or in places where the view is obstructed by a substation building – these are for trains running reverse traffic since people are not likely to expect a train from that direction on that track.

Gated intersections are also handled differently when running reverse traffic. When running normal traffic, the gates are lowered either by a call loop if the platform is right near the intersection (such as the above picture of Elmonica/170th) or when the train enters the approach circuit as it approaches the crossing gate for gates that are not near a platform. There is another circuit that extends 10 feet on either side of and through a gated crossing called the island circuit. When the island circuit is shunted, it will lower the crossing gates if they weren’t already lowered – you won’t notice this running normal traffic since under normal operations the gates will be lowered by the time the train gets there, but when a train is running reverse traffic, it uses island circuits to lower the crossing gates. The operator will wait until the gates have been fully lowered for 10 seconds before proceeding through the intersection.

Manual Block

In a manual block, most of the rules that apply to trains running reverse traffic will also apply to those running normal traffic. For one thing, travel in both directions of a manual block will be done at restricted speed, unless otherwise instructed by Control.

Borrowed picture – Both of these trains are running normal traffic, but it shows switch points as the operator sees them. Here it is a trailing move since the points are facing away from our oncoming train

If there are switches in the manual block, operators in both directions will be required to stop and observe every set of switch points before proceeding, regardless of whether the switch points are facing toward the train or away from the train (as seen in the above picture).

A planned manual block will have a written train order, but operators about to enter a manual block, whether planned or unplanned, will still call Control before they enter to receive specific instructions. The instructions will have to be repeated back word for word, which ensures that there is no misunderstanding of the instructions, since manual blocks have the potential to be extremely dangerous. Even at 20mph, a train splitting a switch (making a trailing move over a power or t-rail switch that isn’t set for you) or hitting another train can cause serious damage. The specific details of the instructions may vary depending on where the manual block is and why a manual block is in effect – for example, a planned manual block may have pullback operators to pull the train through crossover switches so that the operator of the train doesn’t have to change cabs.

Previously, a “medallion” system had been used for manual blocks. A medallion was an object such as a stuffed animal (like the rabbit) that would be passed off to a train as it was about to enter the block. If you didn’t have the medallion in your possession, you would not enter the block. Nowadays that system isn’t used. Instead, a clearance sheet is used to record all train movement in manual blocks. This written record details the movement of all trains into, through, and out of the block, ensuring that only one train is in the block at a time.

Once an operator is clear of the block, he or she will call Control. Their train will be recorded on the clearance sheet, and the operator will then be able to resume normal operation. The next train will then be cleared to enter the manual block. This process continues for the duration that the block is needed. At that point, Controllers and supervisors will ensure that all trains are clear of the manual block and that all switches are aligned normal and locked. The first train through the track that had been out of service may be asked to sweep that section of the alignment, especially if the manual block was due to an emergency, and then following trains can operate as normal.

Rules, train orders, and more

There are a number of rules that govern the movement of trains in the yards and on the mainline. The broadest and most basic set of these is the Standard Operating Procedure (SOP) manual, which lists the standard operating procedure for pretty much every situation that can happen in normal and emergency circumstances (such as what you need to do if your pre-empt times out and you don’t have a secondary call loop or push button). Then there’s the rail operator rule book, which covers the most pertinent information from the SOP manual that an operator will need on a day-to-day basis.

For anything that will deviate from the normal rules and SOPs without being a permanent change to them, a train order or special instruction will be issued. Train orders and special instructions are temporary rules issued by Control that will govern train movement under special circumstances. A train order will last for a maximum of 24 hours, and a special instruction will last for a maximum of one year.

Train orders

Operators are responsible for getting the day’s train orders at the beginning of each work shift, verifying that they are understood, and following them while they are in effect.

A train order will often have a restriction on normal operating procedures, such as requiring operators to reduce speed below the posted speed limit in an area or to call Control for permission before selecting at a platform. One common example of a situation that will have an associated train order is the presence of workers in the right of way. This could be for signal or switch maintenance, a walking inspection of the track and overhead wires, litter patrol, etc.

Workers in the right of way (top) are protected by a call board at PGE Park (bottom), which is governed by a train order. Here the call board is used because of limited visibility around the corner from this platform.

Train orders can also include customer service information – for example, a train order can require operators to make announcements to passengers about any unusual circumstances that may affect their travel related to the train order (like when there’s a major interruption to service).

In addition to written train orders that generally are related to planned events, verbal train orders will be given when an unplanned situation arises that requires something different from standard procedures. For example, if a crossing gate fails, a verbal train order will be issued for operators to stop and call Control from the platform before the failed gate. Last weekend’s Galleria action was a recent example of an unplanned situation with a verbal train order: because of police activity on the platform, operators were instructed to proceed at walking speed from Park Ave, stop at Galleria without opening doors to call their signal, and then continue west. When a verbal train order is given, operators will repeat the train order back to Control word for word to ensure that they understand what is required. A verbal train order always takes precedence over any written train orders, rules or standard operating procedures.

Special Instructions

Train orders are best for short-term changes to normal operating procedures that won’t last more than 24 hours. If the changes will need to last longer than 24 hours, a special instruction will be used. Because a special instruction can last for a year, these will be issued for ongoing situations such as construction on part of the mainline. If the operating rules around a situation like that are not likely to change within the year, it makes more sense to issue one special instruction rather than a new train order for every day that it’s in effect. A special instruction takes precedence over written rules or SOPs, but a train order will take precedence over a special instruction.

In addition to the above rules, relevant information is distributed to operators in several ways. Sometimes this is done verbally over the air where a Controller will give information for all trains affected by something (for example, a substation going offline which will affect how operators leave platforms.) Other information is distributed in written format, via maintenance advisories, Trainlines, and other postings.

Maintenance Advisories

A maintenance advisory is an overview of what’s going on on the alignment for that particular day, and it gives operators information about circumstances that will involve people on or near the ROW or events that will result in unusually crowded platforms. A maintenance advisory will include things like city construction work that doesn’t directly involve the trains but may be occurring near the alignment, such as the painting of road lines or bike boxes. It also lets operators know if any non-TriMet people have track access permits (e.g. when video crews film on part of the alignment), if any training will be taking place on or along the alignment (e.g. new rail operator, new supervisor, or new Controller training), or any public events (e.g. Blazer games) that will result in a heavier than normal passenger load.


Trainlines are one-page newsletter-type postings  put out periodically by the rail training department. Topics covered by Trainlines vary – many are about best practices for a variety of operational matters such as adjusting mirrors on the trains (shown above) or keying in, reminders of safe operation when leaves are falling, reminders of rules or speed limits along the alignment, or sometimes just common courtesy.

Operators are responsible for strictly following all SOPs, rules, special instructions, and train orders, and information on all of these is always readily available because of how important it is that everyone clearly understands them. I know as part of this recent focus on safety,  people have suggested that safety information should be posted in operator break areas, but that has already been going on long before the recent safety efforts. The pictures below are from the break room at Expo (just as an example) where copies of special instructions, Trainlines, and other safety communications are regularly posted.

One year later

This picture has nothing to do with anything
I just like it and haven’t had any place to use it yet.

This blog is  a year old today, and it’s been an interesting year.. when I started I didn’t really know what to expect. The main topics that people blog about (and want to read about!) seem to be how to cook, how to be a writer, or parenting advice, but not so much light rail. So I didn’t know if there would even really be an audience for this sort of technical information, since there’s no food involved, no pictures of babies, and I’m not good at telling interesting stories (even transit related ones like what EMS or Dan Christensen write) that people enjoy reading.

But I like putting this kind of information out there. As far as I’m concerned, only good can come from sharing information. While on the trains, I’ve talked with a lot of passengers who are curious about how things work (most asking things like “what’s the top speed?” or “how do you steer?”) and I really like doing that, because I sort of figure that anyone who wants to take the time to learn about the trains is not going to be someone who is going to run or drive in front of a moving one. I much prefer teenagers asking how the signals work to teenagers who think it’s fun to “pretend” shove each other in front of a train as it comes in to the platform.

Gateway art

Also, since there aren’t a lot of light rail blogs, I’ve found that when people do websearches for things like “trimet signal n60” (I’m still curious why someone was looking for that one) or “train to wayside communications vetag” or “Trimet ‘auxiliary track'” or the extremely popular “arcing pantograph”, they end up here. Most visitors don’t comment, but I kind of hope that they find what they’re looking for when they read one of the posts here. I want to see if there’s an easier way for people to find posts here – the search function is pretty good, and I’ve got all the tags & category links at the bottom, but there’s probably a better way to organize things.

All in all, it’s been a good year. Here are some stats, which might be interesting to compare with a year from now, assuming this blog is still around:

  • This is the 100th post, and there are:
  • 552 spam comments (which are filtered out before they ever get published)
  • 22,755 site visits
    • March of 2010 I had 349 visits – so far this March I’ve had 852
  • 533 images

I intend to keep writing, because I still think TriMet needs much more public outreach (I’ll be keeping an eye on the new Safety Education Committee), and I guess this is my way of contributing where I see a gap. If people walk away from here having learned something, then mission accomplished. And I know a few operators and at least one Controller that read this blog, and your perspectives and contributions – if you would like to weigh in – are welcome. I’d never specifically planned for this blog to be a one-man show, so the more input the better.

Anyway, thanks for reading, and your comments and questions. Here’s to another year!

SOPing an intersection

In my last post about the mall, I mentioned how the intersections on the mall have secondary call loops, that is, call loops that are not located at a platform. Normally, operators don’t need to use these because the signals will be cascading from when the pre-empt at the platform was called. Secondary call loops are there to be used if the signal times out before the train gets to that intersection – they allow operators to quickly recall the signal to keep moving. That’s not the only way to get a pre-empt again – as I’ve mentioned before, some intersections are equipped with a push button, where an operator can reach out of the cab window and use the push button to recall the pre-empt.

However, not all pre-empted intersections have push buttons or secondary call loops. For example, on most of Burnside (which uses mass detectors instead of call loops) a train cannot get a permissive signal again if the pre-empt times out or fails to display a white vertical. Continuing through the intersection on a yellow horizontal is the equivalent of running a red light for a train – it’s a rule violation and it’s dangerous.


So if it should happen that a pre-empt times out or fails to change to a white vertical in the first place, and an operator has no secondary call loop or push button, there is a set standard operating procedure (SOP) to safely proceed through the intersection. If you’re listening to the radio and you hear an operator requesting permission to SOP the intersection, what they’re asking for is clearance to proceed on a yellow horizontal.

First, the operator has to stop the train before entering the intersection on a yellow horizontal. Next, they call Control for permission to SOP the intersection. If it is an intersection that can be safely SOPed*, Control will tell the operator to wait for a fresh parallel green and walk sign. Where applicable (e.g. on Burnside) the operator will also have to wait for a red left turn arrow.

*Not all intersections can be safely SOPed – here heading west into Goose Hollow, Collins Circle at 18th & Jefferson has a secondary call loop. However if an operator overshoots it, they will not be able to SOP the intersection

When the auto traffic lights have a parallel green and red left turn, the rail operator will  sound horn warning and proceed when safe. This includes checking for emergency vehicles. As seen from 2005, an emergency vehicle’s Opticom can’t make a white vertical go back to a yellow horizontal, but if they placed their call before you it will prevent a white vertical from coming up at that intersection.

Train vs Fire Truck, Hillsboro, 2005.