A question regarding real life AC units

[JackClare1995]

Hello all

I've recently been thinking, can Class 323's run doubled up? I was thinking, if they were to do it, would they lower one pantograph and get the power for all four motor cars through the one pantograph, or would they keep them both up? I only ask because on the 390 there seems to be two pantographs but only one ever seems to be raised. This got me thinking, if two AC trains are connected together, can they both have their pantographs in contact with the wire? Then of course, I remembered about Manchester Metrolink trams having both pantographs raised when operating as doubles (however these trams are DC).

So, anyway, can 323's operate doubled together, and why do 390's only have one pantograph raised? The reason I ask is because I plan on operating Northern and London Midland 323's coupled together but I want it to look as realistic as possible.

Please feel free to move this thread if necessary

Jack

 

[Bhorton]

I think it is the same reason why the 8- AC electric loco's have only 1 up. (dont ask me that reason!)

 

[JackClare1995]

Ooh okay! Thanks for the info!

Jack

 

[uracco]

I know on the Pendo's at least that only the rear one is raised. This is due to restrictions on high-speed working with 2 pantographs (no idea why). If you were going from Euston-Birmingham the one on Coach 7 is used. Go the other way however, and Coach 3's panto is used.

 

[JackClare1995]

Cheers for that info

I wonder if they don't allow it because if both pantographs were raised over two sections, they would connect the two separate overhead sections resulting in problems and short-circuiting?

Jack

 

[Vern]

So far as I'm aware the pantograph would be raised on both units, there's no "bus" to transmit high voltage between the two sets. With a 75 MPH or 90 MPH unit you are not going to get sufficient oscillation between the leading and trailing pantograph to have a risk of de-wirement.

 

[shaneturner12]

It's the Class 350/321/390 units and the Class 444/450 units that could have the problem with that.

Shane

 

[nexusdj]

Pendolino's originally had the leading pan up as it made it easier for drivers to judge the timing to shut off and take power whilst traversing neutral sections , It was then suggested by a driver that if they ran with the trailing pantograph raised then that additional distance may give a driver a slightly better chance to lower the pan if they see an obstruction on the overhead wire .

323's run regularly on Birmingham's Cross city line in multiple with both pans up .
Driving technique needs to adjusted when running with 2 or more units in multiple as you have to take into account the increased time needed to coast through a neutral section before taking power .

 

[whitepass]

I do not know how the UK dose it but in the US the back pantograph was used so that if it broke you could use the front one to run the train.

 

[uracco]

After saying what I said, the GNER White Rose 373's used to run at 140mph between Peterborough and Stoke Tunnel with both Pantographs up on more than one occasion.

 

[JackClare1995]

Cheers for the replies, folks I think it's fairly safe to say that 323's and 390's are very different Multiple-Units. I must admit, I've never seen a 323 operate as a double, however of course there is quite a stock shortage with Northern Rail so they can rarely afford to run units as doubles, particularly 323's as all the 323's are taken up on services to Manchester Airport, Glossop, Crewe and Alderley Edge and I've only ever been through Birmingham twice (both of which, at about 22:10 on a Saturday night onboard the 19:15 Cross Country ex-Southampton Central service to Manchester Piccadilly, at which point I doubt there would be double 323's anyway).

Once again, cheers for the replies! Now I just need somewhere to run the London Midland and Northern 323's as doubles :hehe:

Jack

 

[shaneturner12]

I normally see both single and double 323s on the Cross-City line during peak periods (Lichfield T.V. - Redditch).

Shane