I asked this question in a different forum, but it really belongs over here. I was referring to the movie Unstoppable, with Denzel Washington.
At first I thought the basic premise was bogus, but then I read about the actual case.
I never dreamed that any engineer, who was the only one on the engine, would ever get off a moving train and run ahead to line a switch! Is that in any way a common practice? [:|]
Can someone tell me why the engineer wouldn’t just stop the train, then line the switch. The movie gave the impression that he couldn’t stop the train (actually a yard cut, I think, with an engine), so had to run ahead. But if he could outrun the train, then it sure seems like it was going slowly enough to stop. Or was it that the engines’s brake hose was not connected to the cut, and therefore the only brake available was the independent, which he knew would not suffice (I think even in the yard there was some downgrade). Did the cut maybe have “bottled air,” but there was no way to initiate a train-line brake application?
What the hell would posses him to run ahead?
(For those of you not aware of the story, the engineer tripped and fell, and could not get back on the train, which then became a serious runaway. This happened in real life, and the movie was based on tat incident.)
Not an answer to your question, but the engineer was quite experienced and had a flawless record up until that incident. Perhaps he had done it before and never had a mishap? FYI- The locomotive was originally called Crazy 8’s and the movie it was called Triple 7’s or something like that.
Pulling a draft of cars with no air, he probably wouldn’t be able to stop it in time with just the engine brakes. And since RR’s have draconian discipline policies and lose their collective (crap) when someone runs through a switch… well…
A 4K to 6K ton track of cars easily overpowers the braking power of a locomotive even at very low speed - inertia, just keeps on moving and overcomes the braking resistance of the locomotive.
From my understading, he thought he had applied the dynamic brake lever and instead applied the throttle lever. Plausible for certain types of control stands, especially if one is in a panic.
I’ve been trying hard to learn (I read a long article last night), but railroad brakes still confuse me. I thought if a train was detached from its engine, then (unless the air was “bottled” by closing the angle cock) all the train brakes in effect “go into emergency:” the train line suddenly unloads its air, so then the reservoirs apply all the brakes.
Are you telling me that when the air rushes out with the big pfffffffft, that’s not just air from the brake pipe, but rather it’s also from all the reservoirs?
Only if there were air in the reservoirs to begin with. This was a yard move, and the cars probably had all been bled off, hence were just that much rolling weight.
Back when we were tying onto a track in the classification yard to couple and pull it, we’d make the hoses and cut the air in on the first three or four (or so) cars, to give the poor overused Geep a little extra stopping power.
With an emergency application (brake pipe pressure suddenly goes to zero), air from the reservoirs is routed to the brake cylinders. The pressure in the reservoirs will only drop to a certain point, that being where the pressure in the reservoir equalizes with that in the brake cylinders. That’s what holds the brakes in application. There will still be pressure in the reservoirs, hence my “no” answer.
As you saw in the primer, when air pressure is restored to the brake line, the reservoirs recharge and the pressure in the brake cylinders is released to the atmosphere, releasing the brakes. But I digress.
In the case of work in a yard, it’s necessary to release all pressure (bleed off) from the reservoirs as well, so there’s no way for the brakes to apply. This is why it takes so long to completely charge a train - if all the cars have been bled off then all the reservoirs have to be refilled. That can be a lot of air.
If the brake system air on a car is good and tight, an emergency application such as will occur when a car is set out and the air is thus dumped may hold for quite a while. A “leaky” car may only hold that application for a short while.
Here is a control stand with a single controller handle and the selector switch, which determines whether the controller handle will engage traction power or dynamic braking.
I remember reading about this incident in TRAINS, and I’ve wondered ever since why the engineer would consider putting the engine in dynamic braking. It’s my understanding that dynamics are ineffective at low speed (at least in DC locomotives), and since he was engaged in yard work, I wouldn’t have thought that he would consider it.
Lithonia Operator
Yes or No: when the hose gets disconnected from the engine, it also dumps all the air from the reservoirs in the train?
No. Key phrase there is “all the air.”
With an emergency application (brake pipe pressure suddenly goes to zero), air from the reservoirs is routed to the brake cylinders. The pressure in the reservoirs will only drop to a certain point, that being where the pressure in the reservoir equalizes with that in the brake cylinders. That’s what holds the brakes in application. There will still be pressure in the reservoirs, hence my “no” answer.
As you saw in the primer, when air pressure is restored to the brake line, the reservoirs recharge and the pressure in the brake cylinders is released to the atmosphere, releasing the brakes. But I digress.
In the case of work in a yard, it’s necessary to release all pressure (bleed off) from the reservoirs as well, so there’s no way for the brakes to apply. This is why it takes so long to completely charge a train - if all the cars have been bled off then all the reservoirs have to be refilled. That can be a lot of air.
If the brake system air on a car is good and tight, an emergency application such as will occur when a car is set out and the air is thus dumped m
Not something I have any experience with - in fact, we can’t move passenger cars unless they are on air.
Absolutely. Have mercy on their souls if they don’t and the cut rolls away. The employee timetable will have specific guidelines for how many brakes need to be set - and that’s a minimum. The actual number is however many are needed to hold the cars from movement.
Don’t get caught! While a crew could use that practice, you won’t find it in the field. The dispatcher has the delay planned in his/her plan. Doing so for an “early quit” might result in a permanent quit…
If the terminal is a Hump Yard and the arriving train is to be switched over the hump as its ‘next’ move, the car inspectors will perform a arrival inspection of all cars and bleed the air off the reservoirs so the cars can be ‘free wheeling’ over the hump. The single bleed rod can be activated from either side of the car. The inspection also identifies defects that may cause car(s) to be switched for Shop Track attention. Each Hump Yard has its own set of TTSI on how the first cars switched into a Bowl Track are to be handled - if hand brakes are to be used, if skates are to be used, if the configuration of the Bowl Track percludes a free rolling car from exiting the track (many Bowl Track are built with the configuration of a bowl - higher on both ends of the track than at
If the cut released the air, wouldn’t that make the brakes apply? And keep the cut from moving?
I thought the problem with bottled air is that it keeps the brakes in the released position. So if enough hand brakes aren’t set, there … goes … your … train …
The air could (and probably would be) bottled with a set on the train, and this is where the problem lies.
If a leak allows air back into the brake pipe the increase in pressure in the bottled line will likely cause the brakes on the cars to release (as noted in the primer).
On top of that, modern brakes are designed so that air from the emergency reservoir is also fed into the brake pipe, speeding the release of the brakes.
IF you’re going to not set hand brakes, you’re better off not bottling the air, as the emergency application is going to hold for a while, anyhow.