Losing power while leaving station at 2mph

[Deleted]

I'm curious as to why this sometimes happens as it's occured more than once before.

The doors shut and the motor powers up to full power, then suddenly cuts off! Half a second later, the motor powers up again and we accelerate normally.

I'm just curious to why that happens as it is pretty jerky! ;D

For the record, only had it happen at Bethnal Green (EB andWB) since I only take the Central often between Liverpool St. and Mile End.

[Deleted]

Might be that people were pushed up against the doors, thus causing the motors to drop out due to the loss of pilot light?

[Tubeboy]

Is there a section gap there? Help me out Artery!

[edb]

I don't think it is a section gap otherwise i† would happen at the same place all of the time. I think it may be pilot light as quite often when this happens the train op comes on and starts complaining about people leaning on the doors.

[Colin]

The main reason for loss of traction (motors) when starting from a station is indeed a loss of pilot light - but it's not the only reason ;D ;D

There are usually two main causes for a loss of pilot light in this scenario - the first has already been mentioned (passengers leaning on the doors). The second cause is where there is a gap in the current rails (section gap not really being of any relevance); as the train's shoes pick up the current rails again at slow speed, the resulting arc which sometimes occurs cause's the train to "lurch" - which in turn, cause's a loss of pilot light (the train door interlocks are sensitive things you see ).

In both these cases, moving the CTBC to the 'Off & Release' position will usually bring back the pilot light (on C & D stocks at least).

Another candidate, though less likely, are the overloads. I'm not that technically minded, but I do know that it's to do with the traction current supply to the motors - if there's an overload, the contacts break, and we lose power. Pressing the 'Overload Reset' button is the cure in this case. Again the CTBC will more than likely have returned to the 'Off & Release' position as it's normally the first reaction the driver will make in response to any problem - hence the impression of a brief lack of motoring.

[Deleted]

It also occurs at Oxo C e/b... and it's not every train that does it either... Variety of factors include misaligned collector shoes, possible overload. There's a Section Gap at Bethnal... but I never really notice anything... I don't get a message on the DTS monitor about Traction supply probs...

[Deleted]

So my two second release of the ATO start buttons might have been right.....wish I'd never deleted it now......