Atomic Systems

Just looking round the 57 to see how things are set up; does the real one have an interlock to stop you putting it in forward/reverse with the throttle open? the model doesn't for sure. I don't think it should be making power with the brakes on full, either.

The discussion about RPM/traction current is kinda irrelevant with this model given it's already been sorted out properly.

Kariban wrote:Just looking round the 57 to see how things are set up; does the real one have an interlock to stop you putting it in forward/reverse with the throttle open? the model doesn't for sure. I don't think it should be making power with the brakes on full, either.

Once you open the regulator, you cannot move the position of the reverser, weather it be in reverse, engine only or forward does not matter.

There is a thread here somewhere about putting stuff in reverse, I will see if I can find it.
Found it.
http://forums.uktrainsim.com/viewtopic. ... 0#p1269120

Well, that is what I meant; it's pretty easy to script ( and if you do it the brute force way of resetting the lever position, you even get a bit of play in it ), but the 57 locks it when it starts rolling rather than the power controller moving.

There are a few other technical things I'm curious about; the power control system uses air pressure for throttle control, so presumably the small control lag I've noticed in cab videos between opening the throttle and engine spool-up *starting* is pressure building, but if you close the throttle it should dump pressure and start spooling down pretty much immediately? the other thing would be the design of the governor and the rate of spoolup/down ( engine rotational acceleration, I guess ), whether it's linear or some sort of bell shape.

This is the relevant bit

milepost326 wrote:I did it for real with a class 47 at Castle Bromwich whilst propelling light Engine back in 1978.

It was the days when you could drop the reverser into “Engine Only” whilst still moving….

I was just a 17 year Saltley Secondman and “in the seat” driving from the back cab in reverse and dropped it into EO so I could take my feet off the deadmans and lean out the window for a better view of the back of an approach ground postion signal.

When I sat back down in the seat………….YES!!!…… I put it in forward whilst going backwards and opened the power handle and blew the load regulator of the inside of the engine bulkhead. The engine was sat on the cripple road at Saltley for 3 months before being towed to Crewe.

Needless to say the driver… Dickie Allgate…who had previously trusted me…………didn’t any longer!

So whilst in Railworks I NEVER use reverse to stop or slow a train down as the real life experience still embarrasses me all these years later…..

1328

Uh, woah. So they didn't always interlock? hm. Or it was broken

I edited my last post while you were doing that, if you can help there at all?

The interlock is mechanical for the control positions, it doesn't take into account the speed of the train. So how I interpret the above anecdote is:

1) Anticipate need to see signal, from opposite side of cab.

2) Close power controller.

3) Move reverser to Engine Only. This is allowed because the power controller is at Off.

4) Take foot off deadman. This is isolated when the reverser is at Engine Only.

5) Observe signal.

6) Foot back on deadman.

7) Move reverser to Forward. This is allowed because the power controller is at Off.

Open power controller. This is allowed because the reverser is in a valid position.

9) Traction motors appear to have negative resistance due to "backward" motion compared to field polarity, act as generators, current jumps wildly with positive feedback, load regulator is apparently first component to actually fail.

The correct procedure, at least with "modern" (1980s) control layouts, would be to close the power controller, leave the reverser in place, and apply the "deadmans holdover" on the opposite side of the cab within 5 seconds of releasing the foot pedal (and vice versa). I'm not entirely clear on whether the holdover was in place with original equipment.

Originally it was possible to move the reverser whilst moving. However after a couple of nasty incidents, including a high speed fire in an ac electric that killed the crew, and with the coming of single manning. The controls were interlocked and a speed sensor fitted so that this was no longer possible, putting the loco into neutral or eo would result in a brake application. Another incident that sticks in my mind is of a Glasgow driver who put his electric loco into neutral so that he could relieve himself out of the cab door. He fell off the loco (and survived) the (passenger) train coasting on for several miles. I think these mods were made very late 70's early 80's. Certainly they were in place by 1983. For exact dates I would have to look back through 30 years of magazines. DSD holdover switches were fitted from new, there are photos to confirm this.

Just to add to the above.
If you now, move the reverser whilst moving, the dsd kicks in, and you cannot override it, quite simply you grind to a halt.

But interestingly enough in the early years of the 158's you could flick a switch, overide this and put the unit into neutral. Handy if you lost an engine and needed to do a restart without risking stopping and not being able to start again. Said switch was eventully locked in place with a breakable glass bar.

Is it possible for the engine to be turned off when a scenario starts? it has been mentioned in the past that failed engine strtups could also be done.

Cheers

SImon

TheTazman wrote:Is it possible for the engine to be turned off when a scenario starts? it has been mentioned in the past that failed engine strtups could also be done.

Cheers

SImon

Random engine cut outs or failings. Often you hear of trains restarted engines in motion, or stopping and having to restart.

RCH37401 wrote:

TheTazman wrote:Is it possible for the engine to be turned off when a scenario starts? it has been mentioned in the past that failed engine strtups could also be done.

Cheers

SImon

Random engine cut outs or failings. Often you hear of trains restarted engines in motion, or stopping and having to restart.

How "often" compared to the mileage that happens without any dramatics?

Apparently some first-gen commuter DMUs would regularly lose several engines on an 8 or 12-car train during the heaviest part of the rush hour. Regularly, as in "every day". Possibly the cooling system wasn't quite up to the extra stress caused by an overloaded carriage.

At the opposite end of the scale, 185s routinely stop one or more of their oversized engines while in motion to save fuel, and restart them immediately after comng to a halt.

Having a loco fail in a multiple-hauled train would certainly add to the range of possibilities for scenarios. At the moment you can start with a dead loco in train, but you can't change that fact whle en route.

With the 158's it was a regular occurrence to lose an engine in the early 90's, not so common with 156's. Usually either down to coolant or tellus oil (transmission fluid), wasn't helped by the near impossibility of reading the coolant gauge. Remember one night losing one out of 4, then 30 minutes later the other 3 went and coasted the last 8 miles after phoning the signal man to make sure he would give me a clear road all the way in. By then it was no longer possible to restart on the move.