Discussion on electrification and the Marlow branch

[jimm]

It was Greenford I was meaning. Apologies if any confusion caused by attempting to answer two completely separate points in one post!

I see we both came up with the same idea about using a satellite view of Bourne End earlier, within a minute!

It certainly encapsulates the issues there in a nutshell, with that Turbo being the icing on the cake.

 

[Peter Mugridge]

Looking at the satellite picture, if there was a set of points installed shortly before where the line from Maidenhead splits for platforms 1 and 2 it should be possible to enter platform 1 at a wider curve which would allow the points for the branch to be moved far enough along to fit 4 cars without tightening the radius for the branch enough to cause problems?


Rough image added drawn onto the satellite image - apologies, I can't seem to convert it to a .jpg - if anyone else can do this, please do.

Err... strange... only my overlay is appearing even though the document at my end shows the satellite image under it??? HELP!!!!

 

[evergreenadam]

What would be required in terms of infrastructure to provide a half hourly service on the Henley branch?

 

[TheWalrus]

As much as battery operated units sound attractive, they actually present a number of operational inconveniences, so aren't all that cheap.

What are the drawbacks? From what I could see it could be charging while idle at Maidenhead, Marlow and Bourne End, and on peak-time through services between Maidenhead and London Paddington.

 

[HSTEd]

The capital cost of all the charging points and so on, and the specialised new units.
At that point iit would be easier to just electrify and deploy specially built two car electrics.

 

[JamesRowden]

I suspect that through services between Bourne End and Paddington will cease in the 2020s. An off-peak service of at least 10tph between Maidenhead and Paddington could be offered formed of a 6tph Crossrail service and a 4tph Great Western service via Heathrow (running fast east of Heathrow).

 

[jopsuk]

expensive idea, requiring land purchase and demolition- connect the two parts with a double track chord, move the station there...

 

[SpacePhoenix]

Why not use a Parry People Mover operating Maidenhead and Marlow between the peaks with it running solely between Marlow and Bourne End at Peak times with an electric train to / from London at this time?

One change either at Maidenhead or Bourne End at all times.

Don't think that they could build one that wouldn't fall foul of the emissions regs

Am I missing something, why cannot you have 2 car 25KV units?

It would probably be a very tight fit squeezing everything underneath to coaches)

expensive idea, requiring land purchase and demolition- connect the two parts with a double track chord, move the station there...

Looking on Google Earth that would look like a good option CPO enough land for the cord (how much passenger traffic does the station get?)

 

[AM9]

It would probably be a very tight fit squeezing everything underneath to coaches)

There is a precedent for a two-car 25kV EMU, the class 309/1 which was introduced in 1962 and ran until the late '70s when they were converted to 3 then 4-car units.
Such a unit nowadays would have very limited application and would be expensive to provide and operate. Far better to use one of the few remaining DMUs to take passengers to the vastly improved services at Maindenhead.

 

[TheWalrus]

The capital cost of all the charging points and so on, and the specialised new units.
At that point iit would be easier to just electrify and deploy specially built two car electrics.

Then why have FGW agreed to try it for Bedwyn? I thought it would be cheaper then electrifying the whole route?

 

[imagination]

What would be required in terms of infrastructure to provide a half hourly service on the Henley branch?

Theoretically nothing - it already happens in the peaks when trains alternate between platforms 4 and 5 at Twyford, and in Regatta week where half the trains don't stop at Wargrave or Shiplake.

 

[Blamethrower]

as jopsuk said, change the track layout so you don't have to reverse.

Marlow has far too many operational difficulties so why not remove the need to reversing ans electrify the whole thing?

 

[HowardGWR]

as jopsuk said, change the track layout so you don't have to reverse.

Marlow has far too many operational difficulties so why not remove the need to reversing ans electrify the whole thing?

I expect the two (?) property owners north of Donkey Lane may be upset. Of course road access would now be from the existing Bourne End Station on the uprooted line solum.

 

[BantamMenace]

How much land would be freed up by demolition of the old station though? Sell the site to a developer and get some houses built their to part fund the new station. All very nice in theory though.

 

[HSTEd]

Then why have FGW agreed to try it for Bedwyn? I thought it would be cheaper then electrifying the whole route?

It would be, using a simplistic analysis over a sufficiently short interval.
If you do a proper analysis over the sixty year life of the electrification equipment, the costs pile up rather alarmingly - unless you make idiotically generous estimations of future battery technology.

 

[TheKnightWho]

expensive idea, requiring land purchase and demolition- connect the two parts with a double track chord, move the station there...

Frankly, something that should have been done long ago. With little hope of the line up to Princes Risborough being reopened, they might as well restructure the infrastructure to make it better-suited to its current purpose.

 

[Blamethrower]

I think it's doable, with a small land grab from someones garden (which would fetch them a huge sum in compensation anyway) and a station on a curve, jobs a good un.

I have a pet peeve about reversing. If you have to reverse then it's a new route.

Marlow to Bourne End should be a PPM. why was the line to Marlow kept open? Political reason I suspect

 

[TheKnightWho]

It would be, using a simplistic analysis over a sufficiently short interval.
If you do a proper analysis over the sixty year life of the electrification equipment, the costs pile up rather alarmingly - unless you make idiotically generous estimations of future battery technology.

This. Batteries have to be replaced often, and this says nothing about the damaging effects of large Lithium batteries on the environment. That all being said, we still have no idea what the charging times will be like, and whether they will be feasible on anything other than the shortest and lowest frequency lines, and not even all of those as through-routes tend to benefit from electrification for freight and special movement purposes. As electrification becomes more widespread, unelectrified islands will simply prove an irritation rather than a cost-saving measure.

 

[snowball]

I don't know the area, but just from Google satellite view and OS 1:25k, I'd say that a new curve to bypass Bourne End station would require demolition of several large houses. Not only that but it might require a new river bridge to avoid a super-tight curve. And even then it might be too tight for a platform to be allowed on the curve.

I think there's a better chance of track realignments to allow longer trains to use the station, but with reversal continuing.

 

[MarlowDonkey]

I think there's a better chance of track realignments to allow longer trains to use the station, but with reversal continuing.

It's already a very tight curve. You could squeeze in a parallel curve into the longer platform and there are photos showing this before a remodelling in the late 1950s. This would still come in about halfway down the "long" platform.

It's not going to happen, but a better public transport outcome could be to replace the Bourne End to Marlow link with a connecting bus, electrify Bourne End to Maidenhead and run at least some of the services as half hourly through trains to Paddington. 2 * 3 car 117s plus an extra trailer making 7 used to run the through service in British Rail days, so Furze Platt, Cookham and the "long" platform at Bourne End shouldn't need alteration, for four car electrics anyway.

Go back far enough in time and it was the Wycombe railway who built a line from Maidenhead to High Wycombe and points beyond. This crossed the River Thames at a right angle and they built a station "Marlow Road" where it crossed the road to Marlow. Later the Marlow railway was built and elected to follow the river bank just far enough away and high enough to avoid flooding. The consequence of this was that it needed a sharp right angle curve to connect to the Wycombe railway and have a bay platform at the renamed Bourne End station. Following the river to Marlow presumably reduced construction costs by virtue of being flat.

 

[MarkyT]

I don't think a new Bourne End direct chord is feasible. It would have to be built right on top of Donkey Lane so you'd probably have to buy up every one of the estate properties on that road as you'd be removing their access. Six houses at say £2m a pop, that's £12m before you start digging. Granted you could redevelop and recoup some of that, but imagine the politics and ill will trying to CP these 'beautiful waterside family homes' etc. Besides the curve radius would be around 120m, probably unacceptable today without special stock and noisy for any remaining local residents. Certainly impossible to build a compliant heavy rail platform alongside such a sharp curve with acceptable stepping distance.

Better to replace the current junction crossover with a new slightly shorter fully signalled scissors arrangement slightly to the west of the existing junction. Platform starting signals could be placed almost on top of the switch tips as at some London termini, and co-acting duplicate signal heads placed low down on the posts pointing towards the cab window to make best use of the platform length. I think a 3x20m car train might be squeezed into both platforms with these measures, together with some judicious adjustment of the buffer stop positions. A 4x20m car train might be accommodated in platform 2 with the London end car hanging off the platform foul of the crossover, and with the off-platform vehicles's doors isolated by SDO. An additional outer starting signal beyond the scissors could control departure of such a train. A diagram is in preparation . . .

 

[HSTEd]

You only need to reach 60m, then you can put a standard three car electric in.

 

[jopsuk]

But the common GWML fleet (mix of Class 387 and 365) will be four car (80m)

 

[MarkyT]

But the common GWML fleet (mix of Class 387 and 365) will be four car (80m)

True but rather than keep a few turbos for the task at Reading, it would be cheaper if possible to maintain a micro-fleet of 'non-standard' refurbished 3-car EMUs for branch line work, or adapt a number of previously 4-car units (which seems to be possible without the very high cost of new cab ends or main transformers). That could be especially attractive in the longer term in conjunction with other measures that together might allow Reading depot to lose its remaining diesel allocation entirely.

 

[pro4600]

How about a tram/train Bourne End to a new terminus in Marlow proper? Or, of course, just a tram.

I was thinking the same thing. TramTrains would open up much more possibilities, including the extension to High Wycombe. The direct London trains would be lost, but i'm sure that will end up being the case anyway.

 

[HSTEd]

But the common GWML fleet (mix of Class 387 and 365) will be four car (80m)

For now, but the 365s certainly won't last forever.
And a microfleet of 3-car 387s is likely to be far less of a maintenance and diagramming burden than an entirely new class as would be required for a 2-car unit. (You can send a 3-car unit on a 4-car diagram without too much difficulty - and it has all the same parts).

 

[MarlowDonkey]

TramTrains would open up much more possibilities,

Do trams run on 25kv? If not, where and how would they be serviced ? There isn't a statement of quite why the electrification is being canned, but the lack of two or even three car 25kv electrics is amongst the speculation. If a small fleet of Reading based diesels is still needed, adding the Marlow shuttle to the requirement appears to have been decided as the simplest solution, in the short term anyway.

 

[Bletchleyite]

Marlow to Bourne End should be a PPM. why was the line to Marlow kept open? Political reason I suspect

Don't know about a PPM, but how much would it cost to put 750VDC wires up and use off the shelf high-floor trams? They can deal with very tight bends.

 

[MarlowDonkey]

Don't know about a PPM, but how much would it cost to put 750VDC wires up and use off the shelf high-floor trams? They can deal with very tight bends.

No doubt, but how does it get to Reading for servicing? I'm not sure the concept of a guided bus has exactly covered itself with glory, but at least it can function as a conventional bus and go to a bus garage.

 

[Bletchleyite]

No doubt, but how does it get to Reading for servicing?

Same way the PPM at Stourbridge gets to Tyseley or wherever - it doesn't, or if it *really* needs to it can go on the back of a lorry.