Tag Archives: type 4

MAX coupling

Not dead. Just resting.

Coupling Info and FAQs

This is going more in-depth on an old anatomy post where couplers were mentioned. The coupler at the end of each MAX car (with the exception of the A-end of a Type 4) allow for both a mechanical couple and an electrical couple between cars. The mechanical couple is what physically keeps the cars connected, and the electrical couple is what allows the cars to communicate. By design, both a mechanical and electrical couple need to be established in order for the train to move.

Although the Type 1s, 2s, and 3s are capable of being coupled into consists longer than two cars, MAX trains do not run in longer consists longer than that. There are rare exceptions to this (e.g. getting a disabled train out of the way), and yes, some 20 years ago trains were brought back into the Ruby Yard in longer consists but the length of city blocks downtown and the subsequent design of all the train platforms limit the length of MAX trains to two cars.

Note: There are several categories of TriMet employees who are qualified to couple and uncouple cars (operators, supervisors, mechanics, etc) but for simplicity I’m just going to go with “operator” in this post.

The Electrical Couple

The coupling process won’t make much sense without describing this first. At the top of the coupler is the electrical coupler head. Under normal conditions, this is either coupled to another train or covered, but occasionally one with the cover up will sneak through ground inspection without being noticed (or alternatively the operator will forget to switch it back after uncoupling cars).

Electrical coupler head on a Type 2 with the cover raised

There are two positions for the electrical coupler head – electronically isolated and electronically normal. If one or both electrical heads between coupled cars are in the isolate position, there will be no electric communication between the cars. When coupling cars, the first goal is to establish a good mechanical couple, and to do that the car doing the couple will be electronically isolated at the beginning of the process.

This switch inside the cab controls the electric coupling of the train

Coupling cars

First, as with just about everything else done with the trains, the operator will get permission from Control before coupling. Next, they’ll do a ground inspection of the car they will be coupling to in order to ensure there aren’t any safety concerns, such as personnel working on or around the car. They will also make sure that the car they are going to couple to is set to electronically normal. The operator will make three safety stops in the coupling process (because hey, you’re essentially about to drive one train into another train) – the first one car length away from the car being coupled to; the second about 10 feet away, and the third at about 3 feet away to ensure that the couplers of both cars are aligned. Then very slowly, the operator will bring their car forward and couple mechanically to the other car (this happens automatically).

The operator will then perform what’s called a “tug test.” As mentioned in the last section, the car that the operator is in is electronically isolated. When there is no electrical communication between the trains, the brakes will apply. In a tug test, the operator remains in the coupled cab and attempts to put the train in reverse and move. The test is a success if the cars do not move – this shows that the mechanical couple was correctly done because it’s holding the operator’s car (which should otherwise be moving backward) to the car with the brakes applied. If the operator’s train car moves backward, it’s either because the mechanical couple failed and the cars came apart, or the cars were not electrically isolated. A visual inspection of the couplers will also be done.

Next is the “trainline test” which is also done from the coupled cab. The operator will now set the car they are in electrically normal (remember that the car they coupled to is also electrically normal). Now there should be communication between the cars, and the easiest way to test this is to open and close the doors. In the yard, this will be done on both sides of the train, and the operator will watch to see that the doors in both cars open. On the mainline, this will only be done on the doors that are on the platform side for safety reasons. If the trainline test is successful, the coupled cars are ready to go.

The finished product: Two successfully coupled train cars. Note how the electrical coupler heads are raised and the covers are on top of the coupler. When the cars are separate, those will slide down over the electrical head.

Uncoupling Cars

A simpler process – again, always done with permission from Control. The operator will do a safety inspection and then press the “uncouple” button in the coupled cab (pictured in the first section of this post, it has a cover over it to prevent it from accidentally being pressed). Next the operator will back their car from the other one to separate the mechanical couple.

Mainline uncoupling

Uncoupling on the mainline is not preferable, but is sometimes necessary in order to cut a bad car and leave a “sportscar” train in service. The exception to this is, of course, the Type 4s, because they can only be fully operated from one end so they can’t be uncoupled on the mainline.

And then the 4s

The coupling and uncoupling processes above apply to the Type 1s, 2s, and 3s. The 4s are more complicated – as you can see in the above picture, they don’t match the coupler heads of the rest of the fleet. Under each Type 4 cab (the A-end) is  a fold-out mechanical coupler head which can be used to mechanically couple a 4 to any other car to be towed or pushed. Type 4s can’t be electrically coupled to the other types of cars, and are the only cars that have the step of connecting the canon plugs of the cables on either side of the mechanical coupler head to electrically couple.

Mechanical coupler head under the A-cab of a Type 4


What’s that bag over the coupler head? (seasonal)

These covers basically work like shower caps and are put over the coupler heads in snow/ice conditions to prevent ice from building up on the couplers. Metal covers used to be used but I don’t remember how long it’s been since they were.

Why is a coupler off-center?

deformation tube bend

The coupler heads are designed to be able to bend around curves in the alignment, so if you see a coupler like this, it isn’t broken. They should be straightened out during a ground inspection, but sometimes one gets missed. The operator or a supervisor will move it back into place when they see it.

What happens if the train cars come apart?

If that were to happen, they stop – the default position for a train car is “stopped” and the loss of electrical communication will apply the brakes in the trailing car, much like how the tug test works. I’ve heard some people are not comfortable riding in the trailing car due to “runaway train” fears if the cars separate, but the purpose of the tests done after coupling is to ensure that that doesn’t happen, so this isn’t something passengers need to worry about.

Today I learned: The more you write the word “coupler,” the weirder it looks.

One lucky cyclist. And by lucky, I mean an idiot.

Nearly a “train vs cyclist” incident

Last week, a cyclist on Burnside nearly got hit during the classic one-two-punch where a train in one direction blocks the view of a train going the other direction. The good news is, if you obey traffic signals including crosswalk signs, you run no risk of being hit by a train in a situation like that because you will have a red light and a “don’t walk” sign. Unfortunately, this doesn’t work if you’re a dumbass who ignores warning devices. This is also unfortunate for three passengers on the train who sustained minor injuries as a result of the the hard stop caused by the operator using emergency braking to avoid the cyclist.

The story was picked up by the Oregonian, complete with video from the train, as the Type 4s have nice forward-facing cameras. Some of the comments on the Oregonian article were… actually rather surprising. A few people didn’t seem to think this was that big of a deal,  saying that the cyclist was “obviously stopping” and “would have waited for the train to pass if the driver had not chosen to stop”, and others feeling that this story was unfairly targeting cyclists.

No, let me tell you something:


Unsafe behavior around the trains is not limited to cyclists. I have seen plenty of stupid actions by people on foot, by people driving cars, and yes, people on bikes. This particular incident wasn’t targeting cyclists, however it was a recent event where people on a train were injured, and a cyclist happened to be the cause. Oblivious people are going to do stupid things around trains regardless of what form of transportation they use. In this case, it was a cyclist. Tomorrow it might be something else. I’m not going to say this guy is representative of all cyclists, but I will say that he’s representative of the boneheaded things people do around the trains.

Video by punkrawker4783 showing pedestrians & drivers acting unsafely

As for this not being that big of a deal? With all due respect, you watched a video in an article titled “Bicyclist prompts emergency MAX train stop in Gresham.” You knew what this video was going to show and you were watching for it. And that’s sort of like watching Titanic where you know what’s going to happen (SPOILER ALERT: The boat sinks) so it’s not a surprise when you see it. But consider this from the operator’s perspective for a moment, who didn’t know that this was going to happen at that intersection.

As an operator, you are aware that every single time you pass a train stopped at a platform on the mainline, there is a chance that someone is going to run around the back of it into the path of your train. You also know that cars waiting to turn left – like the one in the video – might run that light. So you reduce your speed (as the operator of that train did) because of those chances, but you never know that this intersection is going to be the one where someone darts out in front of you. But when it happens, you are going to brake hard to bring the train to a stop to avoid hitting them.

Diagram of a Type 4’s cab from the outside. The camera is located at #7

Consider too that the video from the train shows a view that is from a fisheye lens mounted close to the windshield near the top of the glass, so you’ve got a great field of vision in the video. Compare that to the operator’s eyes, which are not fisheye lenses and are situated much lower and further back from the windshield than the camera. Additionally, those pillars on either side of the windshield form a considerable visual barrier:

Left-side pillar in a Type 4

So the view you see in the video shows the cyclist – who you were expecting to see – likely before he entered the field of vision of the operator (who was not expecting to see him). And yes, suddenly seeing someone heading into the path of your moving train is a big deal. People have been killed doing the exact thing this cyclist did. To state the obvious, trains don’t swerve. You have a split second to react and hit the brakes when you see someone who isn’t paying attention and is on a collision course with you, and that’s all you can do – you’re not going to keep going, assuming that they will stop.

To the person who said to train MAX operators not to use the emergency brake… are you serious? Emergency braking on the Type 4s is explicitly covered during Type 4 training – when I did mine a few years ago, we took a 4 onto the test track at Ruby, brought it up to 35 mph, and used the emergency brake to practice both using it and recovering out of it in a controlled setting before encountering situations like this. And yes, the emergency brake is a hard stop, even harder if you’re using it at a low speed. But what other option is there? Run the risk of killing someone who isn’t paying attention?

Operators are not mind readers. I see a cyclist heading on a collision course with a train, and my instinct is to stop the train, not to assume that he’s going to wait for me and then cross behind the train. I can’t tell if he’s obliviously ignorant or intentionally suicidal, but I’m not going to waste a lot of time mulling it over, I’m going to do what I can to not hit him.You don’t put your faith in someone incapable of obeying a red light/don’t walk sign to have the intelligence to get out of the way.

Incoming westbound train, Millikan Way

Some people suggested putting up mirrors in areas where the view of a train might be obstructed. Those are already in place in a few areas of the alignment, such as the above picture taken at Millikan Way. However, similar to crossing gates, warning lights, and don’t walk signs, these won’t help you if you willfully ignore them.

Oh, and one more thing?

Among other things, reading was not this gentleman’s strong point

Yeah, riding your bicycle is not permitted on the train platforms in the first place. Had someone been doing code enforcement on that platform at that time, he could’ve been looking at a $175 citation (or more) before getting the chance to put himself – and others – in harm’s way.

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 operation in the news

Really nice segment about MAX operation done by KATU.

Watch it, love it, show it to all your friends. It’s so rare for the public to be able to get any glimpse of “what it’s like” to be a rail operator, so I’ve been looking forward to KATU publishing this story. And Pat is easily one of the best ambassadors I can think of for this job. He and I have talked before about how there needs to be more outreach for the public to see things from this perspective – both in terms of safety and just for a general “here’s why things work the way they do”.  But there’s a limited number of things that we are able to do on our own, so any big news coverage like this is fantastic.

“Type 4s” elsewhere

We call them Type 4s since they are the 4th kind of train in TriMet’s fleet, but the actual vehicle model (Siemens S70) is used in several other transit districts where it wouldn’t be called that.

Here’s a look at the Utah TRAX version – like all other versions of this train with the exception of TriMet, there’s a cab in both ends (ours has a cab only in the A-end). TRAX apparently requested a shorter model for their trains as the cabs look smaller and the front of the train seems to be more blunted than TriMet’s. The interior seating configuration is also different.

And here’s how one of the cars is built in a video for Norfolk’s TIDE light rail.

This is someone’s video out the front of one of the cars in San Diego. I envy the mirrors on the San Diego trains – TriMet decided to use cameras instead of external mirrors for the Type 4s, which are not nearly as effective as mirrors.

Right-side camera in a TriMet Type 4

In Charlotte on the LYNX.

And Houston’s METRO, which has the dubious honor of being the one of the most accident-ridden light rail systems.

Et en France, il y a le tram-train qui utilise ces mêmes trains Siemens. Cette vidéo de “burn-in” montre l’extérieur, et aussi quelques vues de l’intérieur. Mais la configuration de la cabine est assez différente de la nôtre:

L’intérieur de la cabine

And the inside of ours – (photo archived by Jason McHuff, not sure who originally took it)

Type 4, the day it was unloaded at Ruby Junction

The Type 2s and 3s (official model is Siemens S660) and the specific Bombardier model that is our Type 1 weren’t used by other transportation agencies as far as I’m aware.