But you don't get a "load shed" immediately.
No, once the driver presses the shoes up button to raise the shoes and open the MCB it takes 15 seconds or so. Then the unit goes into load shed: the cyclops light goes out, the cab fan stops, the cab light goes out. The instruction Southern have issued is to wait for the cyclops light and cab light to go out before pressing AC system select + pan up. While the pan is being raised and the MCBs are closing, the unit is definitely in load shed.
I've coasted quite some distance in Cl379s when the power to the OLE has tripped out before the TCMS warns of a "load shed". But even when it does commence it is done in a staged manner that can take up to 90 minutes to complete. Most passengers probably wouldn't even be aware of the unit slowly shutting down systems around them for quite some while.
Well, in this situation the passengers are very much aware. Load shed does take up to 90 minutes but it's a systematic process and the first systems to shut down are, as I said, those with a heavy drain on the batteries which go out pretty much immediately - e.g., saloon air con and lights. If you're in the saloon when the changeover occurs, there are always a few passengers who stop talking mid-sentence and look at each other when the lights dim and the air con fans die, clearly wondering whether the train has broken down. (Similarly, there are often a couple of passengers in the PTOSL sitting near the toilet who look a bit alarmed at the loud clonks when the VCB opens and closes at a neutral section on the OLE)
"Load shedding" surely isn't a very good reason for Cl377s not being able to change from DC to AC on the move.
I don't think anyone's suggesting it is.
I would imagine that it has more to do with each TOCs driving policy.
Yes, and it's Southern's policy not to do it on the move even though, technically, it is possible. As far as I'm aware the reason for this is nothing to do with load shedding, it's more to do with the fact that a) if the pan doesn't go up, then there's only a short stretch of 3rd rail before it runs out which leads to the risk of a train becoming stranded off the juice (the turnback shunt at North Pole (the shunt on the mainline, not in the turnback siding) requires the driver to go to the very end of the juice rail before changing ends) and b) because the signal where the changeover takes place can be at red as it protects North Pole Jct, so it's a means of avoiding a SPAD should the driver be concentrating on raising the pan instead of the signal.
There are 2 main reasons why LOROL have introduced the changeover on the move at north pole.....the other is to try to prevent doors being released where there is no platform present
I've heard that too. But it seems a strange way to deal with that problem. I've also heard that doors have been released while the train is standing at a red, but I don't imagine LOROL would suggest not stopping at a red.
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:roll:
