Is it normal for the pantograph at the front, or the rear, to be raised?

Moderator note: Split from https://www.railforums.co.uk/threads/tpe-nova-1-class-802-2-progress.163414/page-31

mikemcniven said:

802207 on Saturday departing Newton-le-Willows bound for Newcastle after I had alighted, was quick off the mark/QUOTE]

Running on the rear pantograph as well now!

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EE Andy b1 said:

Running on the rear pantograph as well now!

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This is common practice because if the rear one is damaged there's a chance that if the OHLE has not been completely brought down the front one can be raised to move the unit rather than it being stuck. Less of an issue with a bi-mode where you can just fire up the diesels in such a case, though.

Bletchleyite said:

This is common practice because if the rear one is damaged there's a chance that if the OHLE has not been completely brought down the front one can be raised to move the unit rather than it being stuck. Less of an issue with a bi-mode where you can just fire up the diesels in such a case, though.

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I was talking to a LNER driver at Carlisle the other Saturday who said that they run with the front pantograph raised so that there’s a chance that they’d see a ‘twitch’ of the wires if they were damaged. Apparently it’s an instruction that they follow.

Some time ago Virgin announced their 390s were running on the rear pan as there was a good chance a driver with good reflexes could drop the pan if they saw a fault on the OHLE. The extra time though brief was thought to be enough. IIRC. E&OE.

The 80X fleet are configured so that the leading Pantograph will be automatically selected when a master key is inserted and the direction selector switch is away from neutral.
I presume this is 802207 in which case the pantograph on the 835207 car is goosed so that's why the rear pan is up!

PennineSuperb said:

The 80X fleet are configured so that the leading Pantograph will be automatically selected when a master key is inserted and the direction selector switch is away from neutral.

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Hope that's whilst under the wires only!!

For several years Class 390s run using there front pantograph in normal operation but then switched to using the rear pantograph as now unless faulty.

EE Andy b1 said:

Hope that's whilst under the wires only!!

For several years Class 390s run using there front pantograph in normal operation but then switched to using the rear pantograph as now unless faulty.

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Yes plus you have to put it in Electric mode, apologies for the error.

On the western its front pan in use on the 80x, unless operating 10. The it is normally front and rear.

What prevents them not using both pantographs?

route101 said:

What prevents them not using both pantographs?

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The risk is of connecting the train to two different OHLE supplies at the same time, so a train is engineered so as to prevent both pans being connected together internally. Trains such as class 700, which run with two pans up, are a special case because they are two electrically separate “half trains”.

swt_passenger said:

The risk is of connecting the train to two different OHLE supplies at the same time, so a train is engineered so as to prevent both pans being connected together internally. Trains such as class 700, which run with two pans up, are a special case because they are two electrically separate “half trains”.

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If one half train fails is there a way for internal equipment (ie lights) to be powered from the other half set if the power collection in the failed half is isolated?

Nick Ashwell said:

If one half train fails is there a way for internal equipment (ie lights) to be powered from the other half set if the power collection in the failed half is isolated?

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Don’t know I’m afraid. Previous discussions have generally been about the half train being sufficiently powered to effectively “rescue” its other half, but the subject of lights etc hasn’t come up.

route101 said:

What prevents them not using both pantographs?

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swt_passenger said:

The risk is of connecting the train to two different OHLE supplies at the same time, so a train is engineered so as to prevent both pans being connected together internally. Trains such as class 700, which run with two pans up, are a special case because they are two electrically separate “half trains”.

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It's not just that. At speed, if the two pans are too close together, the pressure they exert on the contact wire can interfere with each other, causing some nasty effects on the tension of the whole setup.

a_c_skinner said:

Some time ago Virgin announced their 390s were running on the rear pan as there was a good chance a driver with good reflexes could drop the pan if they saw a fault on the OHLE. The extra time though brief was thought to be enough. IIRC. E&OE.

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I also got the impression that when there was OHLE damage and the rear pan was is use, there was likely to be less collateral damage (flying metal etc) than if the front pan was in use.
I think there was some considerable train damage from front-pan incidents (eg bits of pan and OHLE flying down the train).

Nick Ashwell said:

If one half train fails is there a way for internal equipment (ie lights) to be powered from the other half set if the power collection in the failed half is isolated?

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The internal bus bar is fed from either end, same as the air systems, 2 compressors per unit alternating every 24 hours.

route101 said:

What prevents them not using both pantographs?

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There are number of reasons, why single unit cl8xx with 2 pantographs uses only 1:
1. wear and tear =££
2. to close to each other means reduced speed
3. software in "normal" operation allow to raise only one

Two class 8XX units coupled up together have 4 pantograph . Only ones at extreme ends are raised ( happens by default , when pantographs are raised or if diesel mode is switched in to electric ).

It is possible to select different pantographs to power up each unit but it has to happen on the TMS screen.

There are speed restrictions associated with each configuration :

pantograph 1 and 4 - default - line speed (GWR 125MPH)

2 and 4 or 1 and 3 - 100mph

2 and 3 - 80mph

PennineSuperb said:

The 80X fleet are configured so that the leading Pantograph will be automatically selected when a master key is inserted and the direction selector switch is away from neutral.
I presume this is 802207 in which case the pantograph on the 835207 car is goosed so that's why the rear pan is up!

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The GWR units are "turned around" at Paddington , that means set arriving with "pan up" at London end is switched over by the driver that takes set from London at country end .

That doesn't happen just by inserting the key in to the desk at county end , physically driver has to press "pan down" (that drops London end pantograph) , then "pan up" (country end pantograph raises) and then select "electric" mode to close VCBs (Vacuum Circuit Breakers).

Switching from diesel to electric mode (in motion or stationary), by default raises front pantograph (or front and rearmost if 2 units coupled up together).


There are also couple of AC Rule Book Module instructions , as what driver must do in case :

1. Line Light disappear - if pantograph was raised in one of the front 3 carriages , driver presses once "pan up" if that does not restore Line Light , driver must drop the pantograph and coast to suitable location to asses what happened ("drop and coast").

If this same actions were taken but pantograph was raised further than above 3rd coach (or in every case if 2 units are in multiple ), driver has to drop the pantograph(s) and stop ("drop and stop").

2. In class 8xx units there is also VCB (Vacuum Circuit Breaker) light , which normally is not lit .
It illuminates red, when units(s) goes through neutral sections , meaning that breakers are open ( the process of opening is initiated and reversed via track inductor - Automated Power Controller ).

If, after passing through the neutral section VCB red light remains lit , same rules apply as for the line light .

That means driver should press "Electric Mode" button once and depending on the location of the pantograph (or if train is in multiple) , driver should "drop and coast" or "drop and stop" .

In this case the desired outcome is for the red light to "disappear"

I'm over in Switzerland and the moment and the practice here appears to be that where there is a choice of pantograph (e.g. on an SBB Class 511 EMU), it's the rear one that is raised.