Double Pantograph on 91114

[Johnny_w]

So I was having a very nice time yesterday at Peterborough and noticed that 91114 "Durham Castle" has a double panto.

Double Panto! by John W. Davies, on Flickr

S0074007 by John W. Davies, on Flickr

anyone know the reasoning behind this?

thanks,

JW

 

[Bayum]

The second pantograph was introduced to this unit as an experiment, to see if two pantographs would raise punctuality and reliability indicators.

At the time, the 91s were suffering due to their reliability and so other options were sought.

I think I remember that not long soon after, their reliability increased? Not as a result of this I don't think...
--- old post above --- --- new post below ---
http://www.eversholtrail.co.uk/news/class-91-duplex-pantograph-prototype-unveiled

The above is a link to Eversholt who commissioned the work.

 

[455driver]

The principle is good but if the defective pan damages the OHL then the train is still stuck.

It was quite a big modification requiring changes to the cab roof, moving the cab air con module etc.

 

[O L Leigh]

The principle is good but if the defective pan damages the OHL then the train is still stuck.

My thoughts precisely. Also the first pan coming off could still damage the second one or lay across it preventing it from being raised. The arrangement on Cl390s is a bit more logical, but it still doesn't offer a "get out of jail free" card if the OLE is damaged or the power is off.

**EDIT**

A better idea would be an emergency generator set in the DVT in the manner of Chiltern, ATW and Nitwit Rail's Mk3 DVTs. At least it could provide ETS to keep things bearable until the cavalry arrives.

O L Leigh

 

[455driver]

A better idea would be an emergency generator set in the DVT in the manner of Chiltern, ATW and Nitwit Rail's Mk3 DVTs. At least it could provide ETS to keep things bearable until the cavalry arrives.

O L Leigh

Far too simple and effective.

Its all about complicating things now, its the modern way you know!

 

[Intercity91]

The idea was to mitigate against low level damage (essentially Carbon/pan head damage). The trailing pan was to be used in normal running mode in which ever direction it was running in, so that in the event of damage to the raised pantograph the other pantograph was unlikely to be damaged.

At present one of the pantographs is isolated (has been for some weeks) and only the pan nearest the outer end of no. 2 cab is in use.

 

[edwin_m]

Even if it is thought to be a good idea technically, the ROSCO is unlikely to modify the rest of the 91s unless they have a long-term contract that will earn a return on the investment. With IEP arriving in a few years that won't be on the ECML.

 

[jopsuk]

At key times of year, the DVT more or less fills up with luggage. How would you cope with Christmas if you halved the size of the available DVT?

 

[O L Leigh]

Do the jenny sets take up half the Mk3 DVTs? I ask because I don't know just how much space they take up. For the relief they would bring in the event of a dewirement, surely it would be worth considering.

As for Christmas, I can't see the problem. HSTs don't exactly have enormous luggage capacity in the powercars or TGS. How do they cope? I thought most people wanted to keep their luggage close by them in the coach, either in the overhead rack, between the seats or on the stacks at the coach ends.

O L Leigh

 

[cjmillsnun]

Do the jenny sets take up half the Mk3 DVTs? I ask because I don't know just how much space they take up. For the relief they would bring in the event of a dewirement, surely it would be worth considering.

As for Christmas, I can't see the problem. HSTs don't exactly have enormous luggage capacity in the powercars or TGS. How do they cope? I thought most people wanted to keep their luggage close by them in the coach, either in the overhead rack, between the seats or on the stacks at the coach ends.

O L Leigh

Yep they pretty much do. This is the interior of 82304, one of the Chiltern DVTs

82304 interior by (Mick Baker)rooster, on Flickr

 

[jopsuk]

The luggage capacity of both power cars plus the TGS is probably equivalent to the luggage space of the DVT- the DVT is also usually used for additional catering supplies.

At Christmas, especially with services to and from Scotland, the sheer amount of luggage results in them running a check in service. There simply isn't space in the carriages for everyone to take what the NRCoC say you're allowed to take as luggage- and lets be honest, a lot of people are taking larger bags. They also continue to take bicycle bookings, so that space has to be left clear.

I think they do luggage check in on some other bank holidays, possibly at Edinburgh Festival time?

At other times, it is common for the bike spaces to be well used.

Chiltern and Arriva are running shorter trains on routes that don't have this huge seasonal peak.

(I should add that I'm one of the horde of Scots and north easterners living in southern England that typically heads north at Christmas, I've got plenty of experience of this!)

 

[DaveNewcastle]

I understand that on the unit in question, the no 2 end cab doors are not available for use. So by attempting to increase availability in one respect, it is reduced in another.

The principle is good but if the defective pan damages the OHL then the train is still stuck.

That is exactly the point I've had made to me by East Coast drivers when discussing the, er, experiment.

This was fitted about 18 months ago and I had thought it would have been removed by now as an unsatisfactory solution to overhead problems.

 

[455driver]

Why take the loco out of service just to remove it, just pull the fuse out and leave it in place for now.
It can just be left there until the next major exam.

 

[Taunton]

May not be generally realised that until the Class 86 came along in 1965, electric locos generally had two pantographs, one at each end. On the first 25Kv locos they used whichever was trailing. On the 1500v Manchester-Woodhead-Sheffield line they normally ran with both up at all times.

http://www.google.co.uk/imgres?imgu...ct=rc&uact=3&dur=2124&page=4&start=51&ndsp=20

 

[O L Leigh]

At key times of year, the DVT more or less fills up with luggage. How would you cope with Christmas if you halved the size of the available DVT?

Well then, I guess that's that. I shall certainly remember this when the next episode of moaning starts when there's a stranding on the ECML due to a dewirement.

O L Leigh

 

[Johnny_w]

Very interesting stuff.

I'd love to know (just for my own titillation) how often the 2nd panto has to be used due to failure of the first.

I was always under the understanding that when panto failues happened it tended to bring down the wires anywas so 2nd would be arguably pointless?

JW

 

[najaB]

I was always under the understanding that when panto failues happened it tended to bring down the wires anywas so 2nd would be arguably pointless?

Not when it's a failure to raise.

 

[edwin_m]

Do they have hollow carbons? I seem to remember from somewhere that there was an air connection to the carbon so if it wore down or broke it would dump the air that held the pan up. A fault of this type might not damage the wire but would prevent the pan involved from raising again.