some bloke
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Would anyone like to guess how fast the train would have entered Euston without braking, from the first graph?
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Train driver 'freewheels' broken down train 13 MILES to London Euston after a power cut
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Would anyone like to guess how fast the train would have entered Euston without braking, from the first graph?
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Bletchleyite
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It's air pressure.
How do you think they are raised when a unit has been shut down?
How do you create the air pressure if you have no power, though?It's air pressure.
How do you think they are raised when a unit has been shut down?
It’s a bit of an irrelevance though, admittedly, as the loss of air pressure will mean that the pan will have dropped of its own accord by that stage anyway!
There's an auxiliary compressor that is powered by 110v battery supply for initial power-up. As per my post above, that's no good if the driver has allowed the batteries to become flat.
That’s my point, really! A fair point about preserving the batteries to allow normal working to be resumed when the power supply is restored, but would drivers normally consider this vs keeping systems on the train running for as long as possible (for the passengers’ benefit)? Are there any instructions to that effect?
Highlandspring
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One thing which ranks highly on my list of railway oddities I’ve witnessed was watching a class 385 being ‘jump started’ with a boost pack to get enough charge in the batteries to allow the aux compressor to run...
bramling
Veteran Member
There’s a couple of types of Underground train which have an interesting design feature, namely that the 630v line contactors are worked by compressed air. Needless to say the compressors are protected by these very line contactors, so if they open for whatever reason (one of which is traction current going off) there’s no means of re-closing them once any remaining air leaks away or gets used up. To get round this there’s a small secure leak-proof reservoir, which maintains a supply of air sufficient to close the line contactors, however this requires the driver to close a cock which is located beneath seats (so great on a busy train!). Failure to do this results in a foot pump having to be used to power up the train.
I don't deal with the operation of these units in service or what procedures are implemented in "out of course" situations but running these units at any speed without 25kv / auxiliary converter output is risky territory as I mentioned previously. It wouldn't necessarily be dangerous but it would certainly add to the situation if you now had a unit failure (or several) in the middle of a power outage. In my opinion I guess it would depend on the route, with priority to at least get to a station for evacuation whether it's a booked stop or not, rather than attempt to complete the journey that's "x miles away".
I borrowed a Corkerhill 156 to blow up a 350 for pantograph air when it's aux compressor failed a few months ago!
driver9000
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No. There is no engine auto-start function.
driver9000
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Battery load shedding (2 stages) when power is lost is an automatic system which requires no input from the Driver. The TMS shows that load shedding has started and if it comes to the stage where the unit is totally without power and stranded then the assisting 350 can supply 110v to the dead unit using the cross feed once coupled.
driver9000
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The engine on a 185 will remain at idle if started on the move as the Driver will need to select neutral and then forward to engage the transmission relays on the restarted vehicle.
hexagon789
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And I presume you can't select neutral while on the move? (I believe you can't on a variety of classes.)
driver9000
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Nope. I haven't tried it but I'm sure the switch is locked to prevent that but at very least I would expect a brake application as happens with 14x and 15x.
hexagon789
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Well I guess that's that then, engaging an engine on the move can't be done.
Highlandspring
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I did suggest to the Hitachi fitter that they might have been sensible to install a last resort bicycle pump...
Bletchleyite
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Some units do have a manual pump of some kind for that purpose, don't they?
Highlandspring
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I’ve never come across it though I know the Woodhead EM1 and EM2 locos had hand pumps to raise the pans.
bengley
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If I'm on time I can shut off at Garforth and coast all the way to Leeds
Deepgreen
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The "break"?
Deepgreen
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Brings to mind the line in "The Railway Children", where they ask Mr Perks why the train is going so slowly - "Well it's all up'ill to Scotland in't it?"
Deepgreen
Established Member
Don't you have to try emergency braking in type training? I would have expected all likely performance elements to be covered.
Yes; if your a Trainee. If you are a Trainee and have done a cab conversion then you don't need to do it. Our Trainees can do 3 traction types and only need to do one emergency bake.
If you are a Driver doing a conversion or new traction course then it's not mandatory as the expectation is that you already know how to drive and your driving skill will adjust.
craigybagel
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You can do the entire trip from a standing start at Knucklas to Knighton without taking power. There are a couple of drivers who when it's time to leave Knucklas merely release the brake, and don't touch the throttle.
Supposedly back in the 50s/60s when many services in Ireland were worked by AEC built railcars, they had a design feature where the dead man's handle had to be pushed down with one hand all of the time or else the brakes would kick in. However, if you put the reverser into neutral, it would disable the deadman's and given Ireland's generally flat topography, you could coast for miles and save your muscles!
Supposedly back in the 50s/60s when many services in Ireland were worked by AEC built railcars, they had a design feature where the dead man's handle had to be pushed down with one hand all of the time or else the brakes would kick in. However, if you put the reverser into neutral, it would disable the deadman's and given Ireland's generally flat topography, you could coast for miles and save your muscles!
zuriblue
Member
So did the Class 506 EMUs. Then again they were pretty old when they were withdrawn.
It was easier to hang a bag on it...
hexagon789
Veteran Member
I believe the first generation BR DMUs were like that, the throttle had to be held down or the vacuum would be destroyed. Not sure if the reverser could be set to neutral to negate that though.
73s had a car footpump to pump the shoes down if you had flat batteries if over a juice rail
now the secrete was to isolate the shoe gear at the other end so you only pumped down the bogie at the electrical end this would take perhaps 5-10 mins
but not isolating the other bogie meant you had to charge 3 times as much pipework of course this would take 5 times longer as energy wanes and fully knacker the average driver
you had to have the gear sector in direction off travel [no neutral ]with deadmans handle or overide button on secondmans side by the window depressed to stop brakes applying and prevent the dogs shattering through lack off air pressure them skipping in and out through vibration
hexagon789
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I'm not quite sure I understand - neutral doesn't take the dogs fully out of connection to the transmission or something? Other than its a 4-speed mechanical transmission in which you can only coast in top gear I don't really fully understand the intricacies of it.
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