Class 390 operation

[rail-britain]

I've just been reading some operational information regarding trains with pantographs, which has then been updated in February 2008

Included are some specifications
When a train has two, or more, pantographs the train is limited to 100mph
When a train has one pantograph the train is limited to 125mph

The update from February 2008
When a train has two, or more, pantographs and the distance between pantographs is no less than 85 metres the train is limited to 135mph

Does anyone know the distance between the pantographs on a Class 390?

Will both pantographs on a Class 390 be required for operation above 125mph?If so, will this be done before the train starts that section or whilst at speed and as the train approaches that speed?

 

[The Planner]

Pendo vehicles are 24 metres i think, so Its going to need a 4 car gap between them, but seeing as they are not likely to ever get beyond 125mph it's not really an issue.

 

[rail-britain]

I was under the impression that Class 390 units would be authorised for speeds up to 135mph from December 2008, and subject to the Trent Valley being completed this would be section where that would apply

With each vehicle being 24 metres, then there probably is at least 85 metres between the pantographs then, as the pantographs are at the outer most ends of the train vehicles and there are currently three vehicles between them (in normal formation)

 

[me123]

They're certainly looking at faster speeds on some sections, but I wasn't aware of any definate plans in the near future. But the trains are capable of 140mph so faster speeds may be possible in the future. Then again, there is the issue of signalling at such speeds.

 

[rail-britain]

The last report from VT, was that all parties (VT, NR, and the unions) had agreed that upgrading and operation for 135mph had been approved
There are already details on the latest update at NR that the first phase for 135mph operation has been completed
As you've pointed out though 140mph is not going to be permitted unless there is a signalling upgrade (to include either an extra aspect, or some other additional method) but NR wanted some serious money for that and it was abandoned by VT

 

[The Planner]

Nothing will be running up the TV at over 125mph for a long while yet, I can assure you of that.

 

[The Snap]

Pendo's normally only run with one panto up anyway don't they?

 

[rail-britain]

Yes, the "front" one
Almost as soon as the Class 390 unit arrives at its terminus, for a change of direction, both pantographs are lowered and then returned to having the "front" one
I've watched it a few times at Glasgow Central, and surprised that both aren't raised so that the power source isn't lost

 

[O L Leigh]

Given that the Pendo uses the normal Brecknell Willis HS Pan as seen across the network, I would be very surprised if it is strong enough to be raised at speed without significant risk of damage to, or even loss of, the pan and/or damage to the OLE or even a full dewirement. The only stock that I am aware of that is permitted to raise a pan on the move is the Cl373 Eurostar, but these have significantly different pans and the Channel Tunnel OLE is a slightly different design to that used on the NR network.

I don't "sign" the Pendo, so anything I can say about the operation of it's pans would be pure speculation. Best I don't then.

O L Leigh

 

[Edvid]

OT question - what Brecknell Willis model are the 365s/377s/350s etc equipped with?

 

[O L Leigh]

They all have a version of the Brecknell Willis High-Speed pan.

As I understand it, there are two versions of this pan. One that is a new-fit and one with a third link that is a retro-fit to replace the Stone-Faively "Bicycle Frame" pan. Most overhead electric stock from the BR era that has a Brecknell Willis pan will use the retro-fit design, even if it never had a Stone-Faively pan to start off with, including Cl90's and Cl321's.

The third link on the retro-fit design is a little "kick back" that carries the pan head itself a foot or two behind the top of the upper pan arm and usually has a couple of small aerofoils attached. The new-fit design doesn't have this "kick back" nor any aerofoils, with the pan head assembly being attached in line with the top of the upper arm.

It's a bit hard to explain (and not a little nerdy), but anyone in doubt should either study some pics or spend some time at somewhere like Cambridge or Liv St where you will see both versions.

Eurostars use something entirely different to a totally different design.

O L Leigh

 

[rail-britain]

Yes, I've noticed in the past, especially in the late 1980s, that some Class 86/4s had Stone-Faively pantographs and then appeared to have a Brecknell-Willis pantograph
Presumably this was as the result of losing a pantograph or from a works visit
Also clearly two versions, the other being a thinner lighter version
Presumably one version for train speeds up to 100mph and the other for train speeds of 100mph or more

The only other major change was on the Class 87 locos which originally had a daft looking scissors cross pantograph (sorry, never knew the manufacturers name), but these too were replaced with Brecknell-Willis pantographs to allow 110mph operation with Mark 3a coaches
At the same time the Class 86/1 locos and a small number of Class 86/2 locos were also modified with these pantographs

 

[O L Leigh]

I don't believe there is a thinner, lighter version. They are all the same, as far as I can tell. However, some do appear to be thinner depending how clean they are and how the light falls on them. There certainly doesn't appear to be any difference as a result of the intended operating speeds, as the retro-fit design used on the Cl91's is the same as that used on most 100mph EMU's.

O L Leigh

 

[rail-britain]

There are definitely two versions of the Brecknell-Willis pantograph
I was wondering about it in the late 1980s, then read an article about it
I will try to get a photo of the two