Grand Central: running on one power car only?

[BRX]

I'm on a GC southbound service, sitting in the rearmost carriage. I can hear the front power car making a racket when we're leaving stations etc but the rear power car seems to be running at a constant, low level. Is this normal practice? Is it because of the short formation (only five coaches)? If so, why isn't the rear car just powered off completely?

 

[Sir_Clagalot]

Go and ask the gaurd. I got a message about it, but Im not putting that one here!

 

[BRX]

Go and ask the gaurd. I got a message about it, but Im not putting that one here!

not normal practice then?
Actually there's just been an announcement over the intercom that there's some problem with the power car...
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So the latest is that we came to a complete halt north of grantham. The driver got out and walked to the rear power car to do something to it, then we started moving forwards painfully slowly. Then we come to a stop again with the nose of the train nearly at the beginning of the station platform. Now we are inching forward, and i mean really inching forwards in an attempt to get to the platform. The train is going to be caped here by the look of it.