Class 323 problem?

[150222]

I was on the 1618 Manchester Piccadilly to Hadfield (a 323) on new years eve and a few minutes after leaving Piccadilly the train came to a stop. The driver then got out and the train went silent (pantograph?). During this time several trains passed us. A few minutes later the driver got back in (I could feel the train shaking as he did so) and the noise started up again. There was no announcements however there were no more problems with the train until Glossop where I alighted. There were no problems on the return 1739 Glossop to Manchester Piccadilly (A different 323). Anyone know what the problem was?

 

[northwichcat]

Could it have not been a red signal for your train and the driver had to get out and phone the signalman?

Quite often a Northern stopping service can get held at a signal while express services carry on and usually there's no announcement to apologise for the delay or say what's happening unless it's a delay of 6 minutes or more.

 

[Nym]

And the main transformer only makes noise when traction current is being drawn...

 

[150222]

Could it have not been a red signal for your train and the driver had to get out and phone the signalman?

Quite often a Northern stopping service can get held at a signal while express services carry on and usually there's no announcement to apologise for the delay or say what's happening unless it's a delay of 6 minutes or more.

That may well be it thank you. I did hear the AWS klaxon just before we stopped.
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And the main transformer only makes noise when traction current is being drawn...

Oh OK. Thank you aswell.

 

[Nym]

Assuming you where in the centre coach, you'll hear a buzzing at 50Hz when the transofmer is in use for higher currents, this is electically isolated from traction motors when not being used, hence the knocking you hear when starting from a standstill, if you want to know why, it's something to do with how GTO Thyristors work in drive control systems, they aint easy to control!

If you where in an end coach, it's unlikely you'd hear the transformer buzz, you'd mainly hear the switching frequencies on the motor controller (whines), either way, doesn't sound like anything out of the ordinary to me, IIRC the transformer cuts out when you move the reversing lever into stop. Although I think some have been timeout modified.

 

[150222]

Assuming you where in the centre coach, you'll hear a buzzing at 50Hz when the transofmer is in use for higher currents, this is electically isolated from traction motors when not being used, hence the knocking you hear when starting from a standstill, if you want to know why, it's something to do with how GTO Thyristors work in drive control systems, they aint easy to control!

If you where in an end coach, it's unlikely you'd hear the transformer buzz, you'd mainly hear the switching frequencies on the motor controller (whines), either way, doesn't sound like anything out of the ordinary to me, IIRC the transformer cuts out when you move the reversing lever into stop. Although I think some have been timeout modified.

I was just behind the drivers cab. I always try to avoid the pantograph coach on electrics after my experiance on a 321.

 

[Nym]

You would definitely be sat in silence unless traction current is being thrown about or a compressor comes on then.

GTO Thyristor drives are fun by the way, had lectures this semester with one of the engineers for 87101

 

[150222]

I didn't think it would be anything out of the ordinary but two Man Utd (They must be mad!) fans opposite said "that doesn't look good" and by the sound of their conversation they used the line regulaly. I had never used a class 323 before and did not know what they behave like.

 

[electra27000]

If the pantograph had been dropped, the lights (with the exception of the emergency ones) would also have gone out.

 

[ChrisCooper]

The transformer will still hum even at a stand as it will also be supplying power to the auxiliaries. The only times the transformer would go totally silent would be if the circuit breaker was open, the pantograph was down or the supply was lost. As has been said though you wouldn't hear the transformer if behind the driver anyway, only the motor sounds and any cooling fans. Not sure about the 323s but some EMUs have cooling fans for the rheostatic brake resistors, which will run for a short time after stopping, so that could be the effect of going silent. Either that or the heating fans turned off thermostatically. Not been on a 323 for ages though so can't remember what sounds would be normally heard.

 

[Nym]

OK, I'll clarify the transformer thing, they only make a noise loud enough to be heard by someone who isn't a candid creature when drawing traction current