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Author Topic: Marlow line electrification  (Read 36579 times)
hertzsprung
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« on: May 31, 2016, 01:32:48 pm »

I noticed that electric masts have been erected over a short section of the branch line at Maidenhead over the weekend.  Why is this needed?  I thought that the branch line wasn't going to be electrified, is that still the case?
« Last Edit: May 31, 2016, 07:07:17 pm by hertzsprung » Logged
paul7575
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« Reply #1 on: May 31, 2016, 05:32:07 pm »

It's a safety measure needed so that if the signallers accidentally route an electric train onto the branch, and the driver fails to notice and doesn't stop in time, then it doesn't wreck the OHLE as the pantograph runs off the side of the contact wire and rises up.  It is quite common to have short stubs of OHLE at junctions for this reason.   

I expect that before the current alterations started the OHLE continued along the main lines at Stockley flyover where the Heathrow lines had already branched off.

Installing the first contact wire length would also have the advantage that if a workable solution to operating AC EMUs (Electric Multiple Unit) on the branch is found then they wouldn't have to come back and re-wire the junction.

Paul
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bobm
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« Reply #2 on: May 31, 2016, 05:51:22 pm »

The same principle wasn't applied with the third rail at Wokingham.  On the rare occasion a Waterloo line train is routed towards Crowthorne rather than Bracknell it can take quite a time to get the electric train dragged back on the juice.
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Adelante_CCT
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« Reply #3 on: May 31, 2016, 07:06:23 pm »

I believe this has happened west of Basingstoke as well when a Southampton service fancied a trip towards Salisbury instead.
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patch38
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« Reply #4 on: May 31, 2016, 07:35:31 pm »

They should have kept those Southern Region Motorized Luggage Vans that could run or 3rd rail or battery!
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grahame
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« Reply #5 on: May 31, 2016, 07:47:25 pm »

They should have kept those Southern Region Motorized Luggage Vans that could run or 3rd rail or battery!

I think you'll find that they all still exist in preservation https://en.wikipedia.org/wiki/British_Rail_Class_419
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BBM
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« Reply #6 on: May 31, 2016, 10:13:52 pm »

I remember back in the 1980s there was an occasion one morning when the driver of a Southern EMU (Electric Multiple Unit) accepted the wrong route at Reading Spur Jct which resulted in the train being completely stranded on the non-electrified line running up to the GWML (Great Western Main Line) at Reading New Jct. After about an hour or so it was pushed back onto the juice by the 08 shunter which used to be stabled at Reading Depot.
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patch38
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« Reply #7 on: May 31, 2016, 10:16:15 pm »

My tongue was fairly firmly in my cheek when I typed that (I should have added an emoticon), but that's interesting to know. That must represent one of the highest percentages of preservation for any type of loco or DMU (Diesel Multiple Unit)/EMU (Electric Multiple Unit)?
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paul7575
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« Reply #8 on: May 31, 2016, 10:59:24 pm »

I believe this has happened west of Basingstoke as well when a Southampton service fancied a trip towards Salisbury instead.

That junction used to have a third rail that went quite some way towards Battledown flyover, I think drivers would have to be fairly determined to get off the juice back then, but it seems to have been shortened in recent years.  The current signalling has flashing yellows for the Salisbury route, which can be seen from the country end of Basingstoke's platforms, so EMU (Electric Multiple Unit) drivers ought to get ample warning of a wrong route.

Of course while running off the end of the third rail will cause embarrassment and delays, at least it shouldn't cause any damage...

Paul
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grahame
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« Reply #9 on: June 01, 2016, 07:00:27 am »

My tongue was fairly firmly in my cheek when I typed that (I should have added an emoticon), but that's interesting to know. That must represent one of the highest percentages of preservation for any type of loco or DMU (Diesel Multiple Unit)/EMU (Electric Multiple Unit)?

Can't exceed 100%  Wink ... statistically, preserved unique locomotives such as Duke of Gloucester, or the battery multiple unit (BEMU) are also 100%.
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grahame
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« Reply #10 on: June 16, 2016, 06:59:06 am »

"Funny" business these battery units we're talking about ... I came across some German units from 1955 - https://en.wikipedia.org/wiki/DB_Class_ETA_150 - hundreds were built; lasted 30 years.  I grant you that the GWR (Great Western Railway) network probably has few suitable lines (Marlow shuttle might be one; always change at Bourne End, nice flat run to Marlow) and a special type of stock is really not desirable ...
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patch38
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« Reply #11 on: June 16, 2016, 09:40:32 am »

Whatever happened to the IPEMU (Independely Powered Electic Multiple Unit (train running on batteries)) - http://www.firstgreatwestern.info/coffeeshop/index.php?topic=16320.0 - that was being tested in Essex? I'm not sure there was ever any post-trial discussion here?

Edit: answering my own question with my friend Google: http://www.railmagazine.com/trains/new-trains/batteries-included
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« Reply #12 on: June 16, 2016, 06:12:40 pm »

"Funny" business these battery units we're talking about ... I came across some German units from 1955 - https://en.wikipedia.org/wiki/DB_Class_ETA_150 - hundreds were built; lasted 30 years.  I grant you that the GWR (Great Western Railway) network probably has few suitable lines (Marlow shuttle might be one; always change at Bourne End, nice flat run to Marlow) and a special type of stock is really not desirable ...

Except the aspiration of GWR and the local authority to run a half hourly service Maidenhead - Marlow (needs 2 units)
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« Reply #13 on: June 17, 2016, 11:44:21 am »

Can you fit a 387 in the platform at Bourne End?

Have read a suggestion that there isn't really enough dwell time at Maidenhead (or under the wires) to recharge effectively, but counter-intuitively there might be enough time on the juice to make the North Downs line work.

Of course there's perhaps a half-way house whereby you wire to Cookham (and Wargrave on the Henley Branch), then drop the pan. But of course that's would not be cheap - lots of trees to cut back and possibly a couple of bridges to rebuild and it becomes far more attractive to just leave the Turbos in place and make it the problem of the next franchisee. 
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paul7575
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« Reply #14 on: June 17, 2016, 01:06:32 pm »

A four car unit cannot get onto the Bourne End to Marlow branch via platform 1, the distance from points to buffers is too short.   

The problem isn't really difficulty in electrifying the route, it is that there are no suitably short EMUs (Electric Multiple Unit) that can fit the existing track layout, and a bespoke rolling stock solution is highly unlikely.   

If there was a short AC EMU, then they'd surely electrify.  An AC/battery EMU possibly couldn't fit all the equipment needed in a short train, so doesn't help.

So it is easier to carry on with short DMUs (Diesel Multiple Unit), and kick the rolling stock problem into the long grass.

Paul
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