Charles Ellson wrote:
On Sun, 17 Apr 2016 18:29:31 -0500, Christopher A. Lee
wrote:

On Sun, 17 Apr 2016 20:56:35 -0000 (UTC), Recliner
wrote:

Charles Ellson wrote:
On Sun, 17 Apr 2016 15:27:40 +0100, e27002 aurora
wrote:

On Sat, 16 Apr 2016 09:32:36 +0200, Robin9
wrote:


I'm re-reading G. F. Fiennes autobiography "I Tried To Run
A Railway" and came across his assertion that the Bletchley
fly-over was a monument to those who did not recognise that
the railway should concentrate on a few main routes and
abandon routes which were not self-financing.

It's years since I last travelled on the WCML so I have to ask.
Does the Bletchley flyover still exist or was it dismantled?

Incidentally, a few mile west of Bletchley on the route the
fly-over was to serve lies Verney Junction, now of course
closed for decades. I was there a few weeks ago. To my
surprise the track in still in place and the station platforms
have not been demolished. Nor has the overhead bridge which,
I guess, brought in the line from Aylesbury.

Some background here. Verney Junction was at the heart of a system
of lines designed to serve the disconnected neighboring communities in
the north of the County of Buckingham. The promoters were local land
owners Sir Harry Verney and the Duke of Buckingham.

The first route Completed in May 1850 connected Banbury with
Bletchley. The following year the branch from Verney Junction to
Oxford was also opened. At that time there was no station at Verney
Junction, merely the bifurcation of the two routes. In 1878 these
routes, hitherto operated by the LNWR, were absorbed.

The LNWR showed no interest in constructing the fourth leg of the
system down to Aylesbury, the county seat. So Sir Harry and the Duke
progressed Aylesbury to Verney Junction as an independent route, the
"Aylesbury & Buckingham" (A&B). Had the LNWR agreed to work the A&B,
Exchange Street in Aylesbury would have been a railway.

However, this was not to be, and after conversion of the Maidenhead to
Aylesbury GWR route to Standard gauge, the GWR worked the route
onwards to Verney Junction. A station was constructed at the
junction, were GWR passenger trains terminated, and freight was
interchanged with the LNWR.

After 20 years of this arrangement the Metropolitan Railway reached
Aylesbury, absorbed the A&B, and took over its operation. This
arrangement continued until London Transport reduced the A&B to a long
siding. Eventually the nationalized railway closed all of the routes
in the area.

AFIK the only time the vision of a thru service from the Aylesbury to
Buckingham was realized was the Duke's funeral train.

Would these routes have utility today? Absolutely. Given London's
desperate need for relief to its overflowing population, picture this:
A 25kV Chiltern upgrade from Marylebone taking over the TfL fast pair
north of Harrow-on-the-Hill.

Expensive. Why not electrify from Harrow to Marylebone with 3rd (or
3rd/4th) rail? No bridge and tunnel rebuilding.

No need to take over. By that time it might be sensible to make the
further parts of the Met. (past either Moor Park or Ricky ?) 25kV with
something on the lines of a cross between S stock and a 377/378 using
AC/DC. Harrow to the changeover could then remain dual-electrified
until S stock dies out (which won't be this week), shrinking back the
DC to Baker Street if not eliminating it from the SSL altogether if
one of the original plans to use OHLE could be implemented with more
modern technology.

What's wrong with just using 3rd rail beyond Amersham,

More expensive, obsolete, less efficient and it's heading toward 25kV
territory.

Much *cheaper*, surely? Less efficient, yes, but why should it matter that
it's headed towards 25kV territory? It may be heading for 25kV territory,
but it's actually on DC territory for much of the route there, and the
performance on third rail is fine for a commuter line. Any stock on the
line beyond Aylesbury will surely be dual voltage, anyway.

After the bad experiences with OHLE on the GWR (cost, overruns, signal
failures) and the ECML (unreliability) I think it's foolish to just assume
it's always better than trusty, inexpensive third rail on commuter lines
that were never engineered for OHLE.


just as the DC line does beyond Harrow?

That was electrified over a century ago. The substations used to trip
if 313s ran in pairs so they're possibly still a bit close to their
limit with 378s. If it wasn't for the Bakerloo Line trains it might
have been converted to 25kV by now.

I bet there are bridges that would make that unlikely.

In article

rg, (Recliner) wrote:

Charles Ellson wrote:
On Sun, 17 Apr 2016 18:29:31 -0500, Christopher A. Lee
wrote:

On Sun, 17 Apr 2016 20:56:35 -0000 (UTC), Recliner
wrote:

What's wrong with just using 3rd rail beyond Amersham,

More expensive, obsolete, less efficient and it's heading toward 25kV
territory.

Much *cheaper*, surely? Less efficient, yes, but why should it matter
that it's headed towards 25kV territory? It may be heading for 25kV
territory, but it's actually on DC territory for much of the route there,
and the performance on third rail is fine for a commuter line. Any stock
on the line beyond Aylesbury will surely be dual voltage, anyway.

After the bad experiences with OHLE on the GWR (cost, overruns, signal
failures) and the ECML (unreliability) I think it's foolish to just assume
it's always better than trusty, inexpensive third rail on commuter lines
that were never engineered for OHLE.

You are completely missing the physics. You can distribute so much more
power at 25KV than at 750v DC. DC electrification is really only suitable
for high density lower speed systems. There are no sustained 100MPH third
rail routes for a reason. The amount of power that can be drawn from the
third rail just isn't enough. Remember the Eurostars crawling up Kent banks
before HS1?

--
Colin Rosenstiel

On 18/04/2016 06:41, Charles Ellson wrote:


More expensive, obsolete, less efficient and it's heading toward 25kV
territory.

just as the DC line does beyond Harrow?

That was electrified over a century ago.

Maybe that line was electrified over a century ago, but lots of the SE
were electrified with third rail, most recently the mainline to Weymouth
(in the 90s?)

"heading towards 25kV territory" is a red herring.

--
Colin

wrote:
In article

, (Recliner) wrote:

Charles Ellson wrote:
On Sun, 17 Apr 2016 18:29:31 -0500, Christopher A. Lee
wrote:

On Sun, 17 Apr 2016 20:56:35 -0000 (UTC), Recliner
wrote:

What's wrong with just using 3rd rail beyond Amersham,

More expensive, obsolete, less efficient and it's heading toward 25kV
territory.

Much *cheaper*, surely? Less efficient, yes, but why should it matter
that it's headed towards 25kV territory? It may be heading for 25kV
territory, but it's actually on DC territory for much of the route there,
and the performance on third rail is fine for a commuter line. Any stock
on the line beyond Aylesbury will surely be dual voltage, anyway.

After the bad experiences with OHLE on the GWR (cost, overruns, signal
failures) and the ECML (unreliability) I think it's foolish to just assume
it's always better than trusty, inexpensive third rail on commuter lines
that were never engineered for OHLE.

You are completely missing the physics. You can distribute so much more
power at 25KV than at 750v DC. DC electrification is really only suitable
for high density lower speed systems. There are no sustained 100MPH third
rail routes for a reason. The amount of power that can be drawn from the
third rail just isn't enough. Remember the Eurostars crawling up Kent banks
before HS1?

I'm well aware of the physics. Just how much sustained 100mph (or even
90mph) running would there be from Amersham to Aylesbury?

The line between Woking and Weymouth was electrified in
the 1960s at very low cost. I used to travel on that route
frequently. The third rail system did not stop those trains from
moving fast.

Recliner wrote:
Charles Ellson wrote:
On Sun, 17 Apr 2016 18:29:31 -0500, Christopher A. Lee
wrote:

On Sun, 17 Apr 2016 20:56:35 -0000 (UTC), Recliner
wrote:


What's wrong with just using 3rd rail beyond Amersham,

More expensive, obsolete, less efficient and it's heading toward 25kV
territory.

Much *cheaper*, surely? Less efficient, yes, but why should it matter that
it's headed towards 25kV territory?

The high cost of DC 3rd rail comes from the need for more complex and far
more frequent substations. You can get a lot of 25 kV line covered from a
single feed.

Robin

In article ,
(Colin Reeves) wrote:

On 18/04/2016 06:41, Charles Ellson wrote:

More expensive, obsolete, less efficient and it's heading toward 25kV
territory.

just as the DC line does beyond Harrow?

That was electrified over a century ago.

Maybe that line was electrified over a century ago, but lots of the
SE were electrified with third rail, most recently the mainline to
Weymouth (in the 90s?)

Weymouth was only electrified third rail because Bournemouth was electrified
that way in 1967 and it was an extension of that scheme to eliminate diesel
working and increase capacity.

The game has changed completely since then with power electronics. Dual
system power now far simpler to provide. If electrification to Weymouth were
being done now it could well be at 25KV.

"heading towards 25kV territory" is a red herring.

Not in this case. Chiltern route trains will be going to Milton Keynes via
East-West Rail which will involve 25KV running from Calvert if electric. So
they might as well have the maximum length on that system because it is
cheaper to electrify at 25KV for non-urban railways.

--
Colin Rosenstiel

In article , (bob) wrote:

Recliner wrote:
Charles Ellson wrote:
On Sun, 17 Apr 2016 18:29:31 -0500, Christopher A. Lee
wrote:

On Sun, 17 Apr 2016 20:56:35 -0000 (UTC), Recliner
wrote:

What's wrong with just using 3rd rail beyond Amersham,

More expensive, obsolete, less efficient and it's heading toward 25kV
territory.

Much *cheaper*, surely? Less efficient, yes, but why should it matter
that it's headed towards 25kV territory?

The high cost of DC 3rd rail comes from the need for more complex and far
more frequent substations. You can get a lot of 25 kV line covered from a
single feed.

Like Milton (north of Cambridge) to King's Lynn. Having single feed sections
quite that long has consequences, though.

--
Colin Rosenstiel

wrote:
In article ,
(Colin Reeves) wrote:

On 18/04/2016 06:41, Charles Ellson wrote:

More expensive, obsolete, less efficient and it's heading toward 25kV
territory.

just as the DC line does beyond Harrow?

That was electrified over a century ago.

Maybe that line was electrified over a century ago, but lots of the
SE were electrified with third rail, most recently the mainline to
Weymouth (in the 90s?)

Weymouth was only electrified third rail because Bournemouth was electrified
that way in 1967 and it was an extension of that scheme to eliminate diesel
working and increase capacity.

The game has changed completely since then with power electronics. Dual
system power now far simpler to provide. If electrification to Weymouth were
being done now it could well be at 25KV.

"heading towards 25kV territory" is a red herring.

Not in this case. Chiltern route trains will be going to Milton Keynes via
East-West Rail which will involve 25KV running from Calvert if electric. So
they might as well have the maximum length on that system because it is
cheaper to electrify at 25KV for non-urban railways.

Will the service from Aylesbury northwards to Milton Keynes be part of the
Chiltern franchise? I thought Chiltern had said it wasn't interested. I
thought it was more likely to be part of the future East-West franchise.

I also wonder if the anti-HS2 NIMBYs wouldn't also object to ugly knitting
and rebuilt bridges when third rail electrification could do the job more
cheaply, with less disruption? The infrequent service of small, low to
medium speed trains doesn't merit the much higher cost of OHLE.

On Mon, 18 Apr 2016 16:37:40 -0000 (UTC), bob
wrote:

Recliner wrote:
Charles Ellson wrote:
On Sun, 17 Apr 2016 18:29:31 -0500, Christopher A. Lee
wrote:

On Sun, 17 Apr 2016 20:56:35 -0000 (UTC), Recliner
wrote:


What's wrong with just using 3rd rail beyond Amersham,

More expensive, obsolete, less efficient and it's heading toward 25kV
territory.

Much *cheaper*, surely? Less efficient, yes, but why should it matter that
it's headed towards 25kV territory?

The high cost of DC 3rd rail comes from the need for more complex and far
more frequent substations. You can get a lot of 25 kV line covered from a
single feed.

Robin

Yes, but you have to weigh the cost of that with the cost of raising
bridges and tunnels, and the disruption while doing this.