Thursday, July 14, 2011

Jerky Rides Explained


I've always wondered why Metro is so jerky, especially when pulling into a station or stopping/restarting repeatedly in a tunnel. I'd never experienced this on any other subway system.

In addition to being uncomfortable, the jerkiness in the stations is a huge impediment to the quick egress/ingress of passengers from the trains, as a lot of people tend to want to stay seated or holding on as long as possible, knowing there will be some bucking as the train pulls in.

I got a tip more than a year ago that the major reason for this was the cars, 1000-series, 2000-series, etc., all have different braking and accelerating properties. Some brake harder, some speed up faster. The source said the cars were never meant to be mixed.

We asked Metro then if it was true only to be told it wasn't.

Their reason: It is a common, unfounded operator gripe. Nothing else.

I've talked to numerous Metro sources, operators and others, over the course of months about this, and they all told me the cars do have different braking and accelerating properties. This, they all said, leads to an "accordion" effect with cars bouncing back and forth as some slow or accelerate more quickly than others.

For example, several sources said, the 5000-series brake particularly hard, so a different series car behind a 5000 will likely bump the 5000 as the train slows.

Next time you're on a jerky train, you can really sense how the cars interact with one another when slowing down or speeding up. They're certainly not moving in unison.

One source said mixing the various series of cars was not a safety issue, but that because of all the bouncing, it does lead to greater wear and tear on the couplers that connect the cars.

On the bright side, the new 7000-can't be mixed--because they won't couple--with any of the other Metro cars, so jerking shouldn't be a problem with them. The downside? 7000-series trains can only be rescued by 7000-series trains. That could prove interesting.

Another reason for jerky rides, I'm told, is that there has been an influx of new operators in the past several months. They're simply not as good as veterans. For example, many experienced operators can compensate for the differing braking/propulsion properties, said a source, but the younger ones don't know how.

The last reason for the whiplash experience is that Metro management frequently sends out "hit squads" or "jump out guys" to make sure the operators are pulling up to the end of the platforms. These teams stand near the front of the platform, often disguised in "Hawaiian shirts" said one Metro source who is not an operator.

If an operator pulls too short or long of the mark, even by an insignificant amount, the hit teams will basically storm the operator's cabin and "ding" the operator, which could result in suspension, said a source. The source said that even with an 8-car train, there's about a 10-foot margin of error.

Because of this, operators inch up and up until they're within the limit, even if there's no danger of opening a door still in the tunnel, as source said.

Not only does this cause jerky rides, but it also eats away at dwell time--the amount of time the train stays at a station.

We asked Matt Bassett of the Tri-State Oversight Committee (TOC) about this issue:
If a train operator pulls too far ahead, or not far enough, he or she runs the risk of opening the train doors outside the platform. This exposes patrons to the hazards of the rail environment; live 3rd-rail power, train wheels and electrified train components to name just a few.

The "inching up" phenomenon can likely be attributed to an operator's cautious approach to the 8-car marker at the end of the platform. We're Metro riders too, and we understand the annoyance that this lurching sensation can cause our fellow passengers.

But we at the TOC still believe it's preferable to even the possibility of exposing riders to a dangerous fall to the trackbed. Careful adherence to, and enforcement of, safety rules such as this are essential to keeping the system safe.
A Metro source--again, not an operator--disagreed and said the hit squads were a management gimmick, a waste of time, eroded morale and were nothing more than safety theater because the majority of trains are 6-cars long, and pulling to the front of the platform is next to meaningless. They added that even with an 8-car train, precision within a foot or two was unnecessary.

Other items:
Metro outlines track work for entire year (WMATA)
McDonnell support federal cuts for transportation (WaPo)

Comments (25)

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Metro is covering up a whole host of problems with the mixed trains. It's a terrible idea, and putting the 1000s in the middle of trains made it all worse.
The acceleration/deceleration movements in the station don't bother me so much because it obviously has some reason behind it (moving the train into position, slowing down so that the train doesn't hit the jerk standing too close to the platform edge). No, the thing that needs to be explained is why some operators bounce the train around in the tunnels when waiting for headway.
Just this morning the greenline operator stopped the train outside of Ft Totten and then rolled backwards and forwards just a few feet for about three minutes. This is much worse, and it happens often enough with this operator that it's obvious he does it on purpose. Each time I get just nauseous enough that I wonder if I can make it to the cabin door in time to vomit. Send him a message, you know?
1 reply · active less than 1 minute ago
I get sick to stomach nearly every day on my ride home from the warm train and the jerky ride.
something i don't understand - was this as much as a problem when the trains were automatically controlled? I didn't ride pre-red line accident, so I don't remember the good old ATC days. as a daily orange line rider, i would definitely say this problem depends on the operator. some can be pretty smooth, others have 3 stop/starts in one station. its the worst when you're waiting for headway at a station and you for some reason stop/start 5 times... i don't understand why the train can't just park right at the back of the station and wait without the constant movement.
1 reply · active less than 1 minute ago
As someone who rode regularly from 2005 to 2010, jerky motion wasn't a problem. There were issues with slow sections and car failures as it was the end of the long period of extreme deferred maintenance that contributed to why the system is as miserable as it is to use these days, but when trains moved, they moved smoothly under ATO. Trains stopped where they were supposed to at the 4-car, 6-car, and (rare at the time) 8-car marks. Above all else, if anything anything went wrong, it was a hell of a lot less bittersweet as fares were lower and the boob trinity of the Board, the Administration, and the Holy ATU had a relatively more reliable system and a hell of a lot less investigative journalism, allowing them to more easily conceal their incompetence.
Ughh, I had that inching-up experience yesterday. Train pulled in to the station, but was just a little short of the front end of the platform. Some WMATA guy was running around outside on the platform and the train inched up several times until it was at the very end. It was completely stupid, considering there weren't even any people waiting at that end of the platform. Just a big waste of time.
Simply put. Metro sucks. They will do anything to get out of telling the public the truth. In addition to the jerkyness...I find the rocking back and forth while waiting for a train to clear the platform HIGHLY annoying. Why not just sit until the train can be moved. What is the point of the rocking?!
Do you have any evidence that the 7000 Series will not be compatible _in non-revenue service_ with the previous series, or is that unfounded speculation?

When the RC7000 RFP was issued, there was a requirement that they be capable of iron-to-iron coupling with previous series, so they can recover and be recovered by any other train on the Metrorail system. Obviously not all of the new trainlines pass through, so a mixed set cannot be operated in passenger service, but the recovery issue was explicitly written into the RFP, and I would find it hard to believe that WMATA would allow Kawasaki to drop that from the production cars.
1 reply · active less than 1 minute ago
From all that i've heard and read, the 7000s can not rescue a train of another series. That has a lot of us scratching our heads here.
Yeah, the jerkiness of the trains can be a pain in the ass.
The jerkiness of the employees can be even worse.
On a side note: Have you guys noticed that theres a lot of "Turnstile FAIL" going on at metro recently? Really Metro, you can't get the turnstiles right?
Funny- when I read the headline "Jerky Rides Explained," I thought this was going to be a post about rude Metro riders.
3 replies · active less than 1 minute ago
Good one!
Or metro employees
The propulsion of the 1000 series is DC based, using a series of resistors to control it as the train gains speed. You can feel it as they pull away giving you a manual transmission style ride. If you look at the signal in an oscilloscope you will see a sawtooth wave.
Frankly, though, shouldn't the question not be "why are train rides so jerky" but "how soon until WMATA gets the trains back into automatic mode?"

Even accounting for the additional inertia by units that do not perform to spec, I would trust a computer to handle the deceleration much more smoothly than a human. Or are they saying that even on that mythical day trains start running on automatic, we would still see jerkiness?
RidersSuck's avatar

RidersSuck · 717 weeks ago

If you're not leaning up against the doors under the DO NOT LEAN ON THE DOORS sign, you won't fall on the tracks.
Honestly closing the airport metro station the weekend before Thanksgiving is idiotic. Are there even any metrobusses that run there?
GlenmontGirl's avatar

GlenmontGirl · 716 weeks ago

I am now going to be on the lookout for suspicious characters in Hawaiian shirts at the end of every Metro platform.
This is actually one of the reasons I had to stop riding Metro two weeks ago. I've taken it every day I've gone into work for 4 years. I injured my back three weeks ago and my neurosurgeon told me that in part due to jerking of the rail cars that he wanted me to avoid Metro.

I now have a car and for the foreseeable future I'm no longer a Metro rider. Who says a painful back injury doesn't have it's perks?
metro sucks.
metro sucks...
let me elaborate... They need express trains from the outer-most stations to downtown (i.e., from Shady Grove straight down to Metro Center, NO STOPS). duh-duh-duh-duhhhhhhhhhh... You know how many people would ride that thing if it QUICKLY went from shady grove to metro center without stopping? damn! Also, the thing needs to go more than 30mph. get that thing from shady grove to metro center at 60mph the whole way and charge 10 bucks. people would freeking pay. more people would ride the damn metro if it was quicker.

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