Class 390 question

[sutty]

I've just arrived at Wolverhampton and seen a pendy, it was named something Hero. It looked to have a 3rd rail shoe one of the driving carriages.

Are any fitted with this equipment? It's fitted down by the wheels near the tilting actuators.

Cheers.

 

[Turbostar]

Possibly 390003 'Virgin Hero', but 390s are 25kV ac overhead, not 3rd rail. Prob what you saw was dampers & yaws etc. that are part of the tilt mechanism.

 

[driver9000]

Hanging down off the bogie you will have seen the APC inductor that opens the VCB killing the power when passing through a neutral section. Either side of a neutral section you will see a set of magnets mounted outside the rails on the sleeper ends, the first set causes the VCB to open removing the power and the second set closes the VCB restoring power to the train.

APC - Automatic Power Control
VCB - Vacuum Circuit Breaker

 

[sutty]

Hanging down off the bogie you will have seen the APC inductor that opens the VCB killing the power when passing through a neutral section. Either side of a neutral section you will see a set of magnets mounted outside the rails on the sleeper ends, the first set causes the VCB to open removing the power and the second set closes the VCB restoring power to the train.

APC - Automatic Power Control
VCB - Vacuum Circuit Breaker

Thanks very much awesome technical response. I am satisfied. Cheers, turbo as well for your rapid response.

 

[Crossover]

Has anyone got a picture of the magnets that are mounted on the track for this purpose? I'm sure I will have seen them and wondered what they were but not known?

Also, do any other electric units have such APC's on them?

 

[driver9000]

Yes, other AC EMUs will have APC inductors fitted although wether they are as obvious the 390s depends on the design of their equipment. AC locomotives are fitted too, although some early types didn't and the driver required to manually run the tapchanger down. APC has been around for a long time.

 

[swt_passenger]

Pictures here:

http://www.vortok.com/signalling/train-control-magnets/automatic-power-control-apc-magnet

Click the photos tab, and it shows an older type as well.

 

[Crossover]

Thanks for that - I think I may have seen the yellow versions around.

I'm guessing that means if the train is travelling too slowly on the approach to such an area, it could end up stranded?

 

[Turbostar]

Thanks for that - I think I may have seen the yellow versions around.

I'm guessing that means if the train is travelling too slowly on the approach to such an area, it could end up stranded?

Guess that more or less sums it up, yep. But in this day in age, I'm assuming drivers are trained on the driving requirements for neutral sections, so a stall happening I guess is pretty much non-existant.

 

[driver9000]

There is a potential for that but care is taken to avoid placing signals, stations etc near neutal sections. There is a way out of it which used to involve restting the pan although I'm not sure about todays procedure. Stopping with the pan on the actual dead section is the biggest problem however small the section actually is.

 

[strange6]

Thanks very much awesome technical response. I am satisfied. Cheers, turbo as well for your rapid response.

And he doesn't even sign for the thing! True enthusiast and professional our Driver9000. Fascinating bloke

 

[Wolf_359]

I'm guessing that means if the train is travelling too slowly on the approach to such an area, it could end up stranded?

It's not something that drivers do on purpose, but there are outside factors that play a part in causing it to happen.

I was working a train a few years ago when someone forced the doors apart, the emergency brake came on and we came to a stop in the neutral section.

We then had to sit there for 30 minutes waitng for a rescue train to come and drag us out.

Of course stopping in the neutral section is only a problem when you have one pantograph, if you have multiple pantographs then you can effect self rescue.

 

[captainbigun]

Yes, other AC EMUs will have APC inductors fitted although wether they are as obvious the 390s depends on the design of their equipment. AC locomotives are fitted too, although some early types didn't and the driver required to manually run the tapchanger down. APC has been around for a long time.

An APC receiver is just like an AWS receiver, it contains a reed switch which is operated by the APC magnet. The newer devices use Hall effect to drive some electronics instead. Either way they are interchangable.

Before entering the neutral section the driver should remove power so that you're not entering the neutral section under load. That results in a sudden loss of power which can send a jolt down the train, it also doesn't prolong the life of your VCB/ABB switching all that load!

The tap changer operated vehicles take longer to off load their power (as the tap changer has to wind down to zero) and vice versa when re-applying hence they can lose more speed in a neutral. The really good drivers will have the 'power' hit zero as soon as they hit the APC magnet. The later AC loco classes and units with phase angle or inverter drives don't suffer so much as they can ramp down and up again within seconds, hence you can shut off much earlier.

There's a good video on Youtube here of a well known GBRf man in the chair on an 87 (325 drag). You can hear (at about 1:15) the contactors drop out just before the APC magnets are hit (when the fans stop and there's quiet!).

You can also see the APC magnets on the clip above, oblong objects either side of the track. Some are painted yellow, newer magnets are not painted and are quite small.

 

[western Champion]

An APC receiver is just like an AWS receiver, it contains a reed switch which is operated by the APC magnet. The newer devices use Hall effect to drive some electronics instead. Either way they are interchangable.

Before entering the neutral section the driver should remove power so that you're not entering the neutral section under load. That results in a sudden loss of power which can send a jolt down the train, it also doesn't prolong the life of your VCB/ABB switching all that load!

The tap changer operated vehicles take longer to off load their power (as the tap changer has to wind down to zero) and vice versa when re-applying hence they can lose more speed in a neutral. The really good drivers will have the 'power' hit zero as soon as they hit the APC magnet. The later AC loco classes and units with phase angle or inverter drives don't suffer so much as they can ramp down and up again within seconds, hence you can shut off much earlier.

There's a good video on Youtube here of a well known GBRf man in the chair on an 87 (325 drag). You can hear (at about 1:15) the contactors drop out just before the APC magnets are hit (when the fans stop and there's quiet!).

You can also see the APC magnets on the clip above, oblong objects either side of the track. Some are painted yellow, newer magnets are not painted and are quite small.

Would this driver be the one that used to be a Route Operations Manager (ROM) for VT ?

 

[captainbigun]

I believe so....likes his heritage traction and the odd snack!

 

[western Champion]

But doesn't know his BASIC faults and failures !

Door on No 2 airframe open because the AFT was isolated. Designed to stop the door being closed when isolated to draw it to the drivers attention. He rings one of our instructors for advise because he can't get power.

 

[captainbigun]

AFT has caught many folk out....it causes me much amusement. I've seen governors changed.....err has anyone checked the AFT cock?!

And, in fairness, the cubicle doors on the brake frames are often swinging in the breeze.

I'll remind him when I bump into him next....