"Charles Ellson" wrote in message
news
On Fri, 11 Nov 2011 08:35:12 -0800 (PST), allantracy

To that end, perhaps Overground services from Euston could reverse and
continue in an Amersham direction.

You can't run 3rd-rail stock on the Met.

Not an insurmountable issue though, as seen on the Bakerloo and District,
and the new S stock has apparently been built to allow use on the raised
third rail supply voltage that NR are about to provide around London...

Paul S

On Nov 11, 10:34*pm, wrote:
On Fri, 11 Nov 2011 20:54:41 +0000, Charles Ellson

wrote:
On Fri, 11 Nov 2011 08:35:12 -0800 (PST), allantracy
wrote:

The main benefit of the Croxley Link is connectivity between South
Bucks (on the Met) and the WCML and vice-versa.

To that end, perhaps Overground services from Euston could reverse and
continue in an Amersham direction.

You can't run 3rd-rail stock on the Met.

Charles:

I defer to your knowledge of the infrastructure, but what would have
to be done, and how much would it cost to make this possible?

Educate me.

Regards
JonH

...indeed, as would I. I'd have though they would be compatible as I
thought all TfL's lines used the same 4 rail system of
electrification, but even if they're not, I'd have thought they would
be compatible by historical virtue that the LO shares tracks with (and
is therefore compatible with) the Bakerloo, which used to have the
branch to Stanmore, so effectively operated over the Met between
Finchley Road and Wembley, though in reality only in and out of
Neasden depot. I know a lot of time has passed, but I wouldn't have
thought things would have diverged too much.

On Nov 11, 10:34*pm, wrote:
On Fri, 11 Nov 2011 20:54:41 +0000, Charles Ellson

wrote:
On Fri, 11 Nov 2011 08:35:12 -0800 (PST), allantracy
wrote:

The main benefit of the Croxley Link is connectivity between South
Bucks (on the Met) and the WCML and vice-versa.

To that end, perhaps Overground services from Euston could reverse and
continue in an Amersham direction.

You can't run 3rd-rail stock on the Met.

Charles:

I defer to your knowledge of the infrastructure, but what would have
to be done, and how much would it cost to make this possible?

Educate me.

Regards
JonH

...indeed, as would I. I'd have though they would be compatible as I
thought all TfL's lines used the same 4 rail system of
electrification, but even if they're not, I'd have thought they would
be compatible by historical virtue that the LO shares tracks with (and
is therefore compatible with) the Bakerloo, which used to have the
branch to Stanmore, so effectively operated over the Met between
Finchley Road and Wembley, though in reality only in and out of
Neasden depot. I know a lot of time has passed, but I wouldn't have
thought things would have diverged too much.

On Fri, 11 Nov 2011 22:36:54 -0000, "Paul Scott"
wrote:
Not an insurmountable issue though, as seen on the Bakerloo and
District,
and the new S stock has apparently been built to allow use on the
raised
third rail supply voltage that NR are about to provide around
London...

The difference is the infrastructure, not the trains. The Bakerloo
"shared" bit is +660 outer, 0 inner, so works for both. The Tube
proper including the Met is +440 outer, -220 inner, so no good for
third rail EMUs. Or something like that.

Neil

--
Neil Williams, Milton Keynes, UK

On Fri, 11 Nov 2011 15:24:07 -0800 (PST), Jamie Thompson
wrote:

On Nov 11, 10:34*pm, wrote:
On Fri, 11 Nov 2011 20:54:41 +0000, Charles Ellson

wrote:
On Fri, 11 Nov 2011 08:35:12 -0800 (PST), allantracy
wrote:

The main benefit of the Croxley Link is connectivity between South
Bucks (on the Met) and the WCML and vice-versa.

To that end, perhaps Overground services from Euston could reverse and
continue in an Amersham direction.

You can't run 3rd-rail stock on the Met.

Charles:

I defer to your knowledge of the infrastructure, but what would have
to be done, and how much would it cost to make this possible?

Educate me.

Regards
JonH

..indeed, as would I. I'd have though they would be compatible as I
thought all TfL's lines used the same 4 rail system of
electrification,

LO is a National Railway service run on behalf of TfL on mostly
Network Rail infrastructure. Class 378 stock is 750v 3-rail/25kV
equipped.

but even if they're not, I'd have thought they would
be compatible by historical virtue that the LO shares tracks with (and
is therefore compatible with) the Bakerloo,

It works the other way round (in both senses). The DC line has a 4th
rail bonded to the traction return running rail so that 4-rail stock
can run over it. It used to be wired LT-style as 4-rail but was
converted to conventional feed (with the "extra" 3th rail) in the
early 1970s.

which used to have the
branch to Stanmore, so effectively operated over the Met between
Finchley Road and Wembley, though in reality only in and out of
Neasden depot. I know a lot of time has passed, but I wouldn't have
thought things would have diverged too much.

They haven't. LU trains are still the "intruders" on the DC line.

On Fri, 11 Nov 2011 22:36:54 -0000, "Paul Scott"
wrote:

"Charles Ellson" wrote in message
news
On Fri, 11 Nov 2011 08:35:12 -0800 (PST), allantracy

To that end, perhaps Overground services from Euston could reverse and
continue in an Amersham direction.

You can't run 3rd-rail stock on the Met.

Not an insurmountable issue though, as seen on the Bakerloo and District,
and the new S stock has apparently been built to allow use on the raised
third rail supply voltage that NR are about to provide around London...

Compatibility is not inevitably a reversable function. The shared
sections all involve some re-arrangement of the power supply and/or
signalling systems. You can e.g. send LU and NR electric stock into
Richmond but neither can take the wrong direction at Gunnersbury as
one requires power between the 3rd and 4th rails and the other
requires the power supply between the 3rd rail and one running rail.
Normal LU signalling is not intended to have traction currents flowing
in the running rails.

"Neil Williams" wrote

The difference is the infrastructure, not the trains. The Bakerloo
"shared" bit is +660 outer, 0 inner, so works for both. The Tube proper
including the Met is +440 outer, -220 inner, so no good for third rail
EMUs. Or something like that.

When the Croxley Link is built the section through Watford High Street will
have to have an operative 4th rail reinstated (for the Met trains) but at 0V
(bonded to the running rails for the LO trains. Should there be any
intention to run LO trains on to the existing Met (e.g. a Watford Junction
to Chesham or Amersham service) the Met infrastructure would have to be
altered in the same way as Queens Park to Harrow & W, Putney Bridge to
Wimbledon, and Gunnersbury - Richmond. It would be easier to use LU trains.

IMHO there is a case for the Croxley Link also to be used by trains from
Chesham or Amersham. But I doubt that there's a business case for procuring
new trains for this, and the likely traffic won't justify 8-car trains.
Perhaps a few of the D78 trains could be arranged as 4-car sets and modified
as necessary for future Met signalling. Certainly a better place to use them
than Harrogate.

Peter

On Nov 12, 11:12*am, "Peter Masson" wrote:
"Neil Williams" wrote

The difference is the infrastructure, not the trains. *The Bakerloo
"shared" bit is +660 outer, 0 inner, so works for both. *The Tube proper
including the Met is +440 outer, -220 inner, so no good for third rail
EMUs. *Or something like that.

When the Croxley Link is built the section through Watford High Street will
have to have an operative 4th rail reinstated (for the Met trains) but at 0V
(bonded to the running rails for the LO trains. Should there be any
intention to run LO trains on to the existing Met (e.g. a Watford Junction
to Chesham or Amersham service) the Met infrastructure would have to be
altered in the same way as Queens Park to Harrow & W, Putney Bridge to
Wimbledon, and Gunnersbury - Richmond. It would be easier to use LU trains.

IMHO there is a case for the Croxley Link also to be used by trains from
Chesham or Amersham. But I doubt that there's a business case for procuring
new trains for this, and the likely traffic won't justify 8-car trains.
Perhaps a few of the D78 trains could be arranged as 4-car sets and modified
as necessary for future Met signalling. Certainly a better place to use them
than Harrogate.

Peter

The maintenance issue would no doubt rear it's had again though on
operating non-standard stock. Perhaps keeping them away from the other
children at a rebuilt Wiggenhall Road might suffice...but I think
you'd far more likely end up with too few S7/S8s on an infrequent
service than a correct number of D78s on a frequent one (It's the same
problem as the St. Albans line - infrequent services push passengers
away, but longer services aren't justified by the current loadings.
Make them frequent enough and you'll get the custom I believe). TfL
does seem to prefer to operate for it's own operational convenience
more than passengers most of the time...

On Nov 12, 1:02*pm, Jamie Thompson wrote:

On Nov 12, 11:12*am, "Peter Masson" wrote:

IMHO there is a case for the Croxley Link also to be used by trains from
Chesham or Amersham. But I doubt that there's a business case for procuring
new trains for this, and the likely traffic won't justify 8-car trains.
Perhaps a few of the D78 trains could be arranged as 4-car sets and modified
as necessary for future Met signalling. Certainly a better place to use them
than Harrogate.

The maintenance issue would no doubt rear it's had again though on
operating non-standard stock. Perhaps keeping them away from the other
children at a rebuilt Wiggenhall Road might suffice...but I think
you'd far more likely end up with too few S7/S8s on an infrequent
service than a correct number of D78s on a frequent one (It's the same
problem as the St. Albans line - infrequent services push passengers
away, but longer services aren't justified by the current loadings.
Make them frequent enough and you'll get the custom I believe). TfL
does seem to prefer to operate for it's own operational convenience
more than passengers most of the time...

What a load of nonsense.

We were about to embark at Dover, when
(Charles Ellson) came up to me and whispered:

You can e.g. send LU and NR electric stock into
Richmond but neither can take the wrong direction at
Gunnersbury as
one requires power between the 3rd and 4th rails and the other
requires the power supply between the 3rd rail and one running
rail.
Normal LU signalling is not intended to have traction currents
flowing
in the running rails.

There's no reason what LU stock can't be converted to third rail
operations - cf. 1939 stock on the Isle of Wight.

--
Paul Cummins - Always a NetHead
Wasting Bandwidth since 1981
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