Anna Noyd-Dryver wrote:

You mean the failure to apply for a derogation?

I never got round to posting my observations on the other thread, so I'll
do it here.

The changes to the permitted clearances have been detailed in posts in the
other thread, with links to Roger Ford's writings on the topic. Safety
rules generally do change over time, and existing installations are
generally permitted to continue to operate. In this instance IIRC Network
Rail could have applied for a derogation (on a structure-by-structure
basis) but apparently chose not to (but not entirely - some structures
definitely have much tighter clearances than others).

There are three critical dimensions to be considered during this debate,
however. The first is contact wire to train roof (strictly, to the track).
There is of course a minimum for this, but over level crossings that
dimension is much higher. The dimension which Roger seems focussed on is
the catenary wire to bridge clearance. Between these two is the separation
of contact wire from catenary wire. Under bridges this is squeezed much
tighter - under very tight bridges the two wires are together (known as
'contenary', apparently). However on the GWML this happens comparatively
rarely - ie bridges are being raised by *more* than the minimum that they
need to. Presumably this is related to the desire to spec the GWML catenary
for 140mph - and presumably on the basis that if you're replacing a bridge
structure to raise it by X amount, the cost to raise it by another Y amount
is (presumably) comparatively small.

A tangled tale. I wonder if the figures used for vehicle
clearance have changed, and how they could actually be
accommodated?

Once upon a time... the Class 357 was the base design for the
whole Electrostar family. Strange as it may seem, the range of
wire heights with which it was to be compatible was very poorly
defined. Indeed, at that time, understanding and specifying its
infrastructure was something the railway was very bad at, whilst
somehow magically still wanting everything to be able to run
everywhere. (1)

Work progressed, based on our interpretation of available data,
until a fateful meeting where someone asked "What about
Thameslink?"

When we looked at the new numbers we had been given, it was clear
that, worst case, the wire got alarmingly close to the vehicle
roof, and the downward curving horns at the ends of the
pantograph head were in danger of flashing over to the sides of
the pantograph well. (2).

The mod to the pantograph well consisted of removing a little
aluminium locally from the top of side wall, and adding a section
of insulating capping to ensure that the worst case clearance
distance to metalwork was still sufficient.

IIRC, the suspension was adjusted, to drop the whole train 9 mm.

It was also necessary to move some radio aerials away from the
vehicle centreline to position them a little lower on the roof
curvature.

I simply can't remember now exactly how the mod was rolled out,
but would not have expected them to spend money making the
changes on vehicles to which the pantographs were not fitted.
Likelihood of actually running on Thameslink may also have been a
factor.

(1) Other gauging issues included platform edge/ step plate.

(2) This was much narrower, and had significantly higher sides
than any previous design. I had to fight for every millimetre
increase from the interference fit I inherited from the tender
outline design. A tedious time alongside a draughtsman with a
barely functional 3D graphics package was the only way we could
optimise the clearances between the various bits of HV roof
equipment, which from memory were just over 200 mm.

Chris
--
Chris J Dixon Nottingham UK


Plant amazing Acers.

On Thu, 9 Feb 2017 16:37:46 -0000 (UTC)
Recliner wrote:
wrote:
On Thu, 9 Feb 2017 16:04:47 -0000 (UTC)
Recliner wrote:
wrote:
The vast majority of freight is hauled by class 66 and 70 diesels and the
main electric freight loco the class 92 can run off 3rd rail anyway.

The main electric freight loco is the class 90. Class 92s are little used.

You sure about that? I thought the 90 was a passenger loco that only
occasionally did light freight because its built for high speed, not pulling
power.

When did you last see a class 92 hauling anything? Most electric freight
are hauled by class 90s.

I've never seen either on the NLL tbh. When I used to get the ELL from
highbury I saw maybe 1 freight train a week and without exception they
were all hauled by diesels.

--
Spud

On Thu, 09 Feb 2017 19:42:06 +0000
Charles Ellson wrote:
On Thu, 9 Feb 2017 16:37:46 -0000 (UTC), Recliner
wrote:

wrote:
On Thu, 9 Feb 2017 16:04:47 -0000 (UTC)
Recliner wrote:
wrote:
The vast majority of freight is hauled by class 66 and 70 diesels and the
main electric freight loco the class 92 can run off 3rd rail anyway.

The main electric freight loco is the class 90. Class 92s are little used.

You sure about that? I thought the 90 was a passenger loco that only
occasionally did light freight because its built for high speed, not
pulling
power.

When did you last see a class 92 hauling anything? Most electric freight
are hauled by class 90s.

Class 92s tend to be seen with Channel Tunnel traffic, there is no
current reason for them to be preferred over straight 25kV locos away
from such traffic.

So there's no freight on southern region then?

There is no sense putting in new 3rd rail between two 25kV areas; it
is obsolete, requires more substations and wastes more energy.

There is sense if it avoids closing a major rail line for months on end with
costs upwards of 100m quid!

Plus its only a few miles from acton to gospel oak. They could easily
re-instate the 3rd rail they ripped up back in the day.

--
Spud

On Thu, 09 Feb 2017 14:26:50 -0600
wrote:
In article , d () wrote:
Of course, if they'd simply installed 3rd rail they could have done
it in a couple of months while the line carried on running. But
thanks to stupid DoT rules about no new 3rd rail they've had to close
the line for god knows how long inconveniencing 10s of thousands of
people and spent 100m.

I see our know-nothing Kipper correspondent has just excelled himself with
his ignorance of electrical engineering. Not for nothing has all the third
rail in North London been replaced with 25KV overhead electrification. A
period of self-education would now be in order.

Has it? Guess you haven't been on the ELL at highbury yet then. You'll be
in for a surprise. They only laid it a few years back too.

--
Spud

On 10/02/2017 09:54, d wrote:
On Thu, 09 Feb 2017 19:42:06 +0000
Charles Ellson wrote:
On Thu, 9 Feb 2017 16:37:46 -0000 (UTC), Recliner
wrote:

wrote:
On Thu, 9 Feb 2017 16:04:47 -0000 (UTC)
Recliner wrote:
wrote:
The vast majority of freight is hauled by class 66 and 70 diesels and the
main electric freight loco the class 92 can run off 3rd rail anyway.

The main electric freight loco is the class 90. Class 92s are little used.

You sure about that? I thought the 90 was a passenger loco that only
occasionally did light freight because its built for high speed, not
pulling
power.

When did you last see a class 92 hauling anything? Most electric freight
are hauled by class 90s.

Class 92s tend to be seen with Channel Tunnel traffic, there is no
current reason for them to be preferred over straight 25kV locos away
from such traffic.

So there's no freight on southern region then?

Al diesel hauled round here, which is why they are discussing the
"electric spine" running 25kV from Reading to Southampton.


--
Graeme Wall
This account not read.

In article , d () wrote:

On Thu, 09 Feb 2017 14:26:50 -0600
wrote:
In article , d () wrote:
Of course, if they'd simply installed 3rd rail they could have done
it in a couple of months while the line carried on running. But
thanks to stupid DoT rules about no new 3rd rail they've had to close
the line for god knows how long inconveniencing 10s of thousands of
people and spent 100m.

I see our know-nothing Kipper correspondent has just excelled himself
with his ignorance of electrical engineering. Not for nothing has all the
third rail in North London been replaced with 25KV overhead
electrification. A period of self-education would now be in order.

Has it? Guess you haven't been on the ELL at highbury yet then.
You'll be
in for a surprise. They only laid it a few years back too.

A line with n0o connections to the North London network. One was installed
at Highbury (only for stock transfers) but has never been commissioned.

It seems to have escaped your notice that the North London was once 3rd rail
electrified all the way to North Woolwich. None north and east of Mitre
Bridge Junction now.

--
Colin Rosenstiel

On Fri, 10 Feb 2017 05:25:55 -0600
wrote:
In article , d () wrote:

On Thu, 09 Feb 2017 14:26:50 -0600
wrote:
In article , d () wrote:
Of course, if they'd simply installed 3rd rail they could have done
it in a couple of months while the line carried on running. But
thanks to stupid DoT rules about no new 3rd rail they've had to close
the line for god knows how long inconveniencing 10s of thousands of
people and spent 100m.

I see our know-nothing Kipper correspondent has just excelled himself
with his ignorance of electrical engineering. Not for nothing has all the
third rail in North London been replaced with 25KV overhead
electrification. A period of self-education would now be in order.

Has it? Guess you haven't been on the ELL at highbury yet then.
You'll be
in for a surprise. They only laid it a few years back too.

A line with n0o connections to the North London network. One was installed
at Highbury (only for stock transfers) but has never been commissioned.

You said north london, not the north london line. Since you're such a pedant
you should get these things right.

It seems to have escaped your notice that the North London was once 3rd rail
electrified all the way to North Woolwich. None north and east of Mitre
Bridge Junction now.

I'm prefectly well aware of the that. Your point is what exactly? That because
3rd rail was removed it can't be put back because of some moronic DoT
regulation? No, lets just inconvenience thousands for months and spend 130m
quid instead, far better.

--
Spud

wrote:
On Thu, 9 Feb 2017 16:37:46 -0000 (UTC)
Recliner wrote:
wrote:
On Thu, 9 Feb 2017 16:04:47 -0000 (UTC)
Recliner wrote:
wrote:
The vast majority of freight is hauled by class 66 and 70 diesels and the
main electric freight loco the class 92 can run off 3rd rail anyway.

The main electric freight loco is the class 90. Class 92s are little used.

You sure about that? I thought the 90 was a passenger loco that only
occasionally did light freight because its built for high speed, not pulling
power.

When did you last see a class 92 hauling anything? Most electric freight
are hauled by class 90s.

I've never seen either on the NLL tbh. When I used to get the ELL from
highbury I saw maybe 1 freight train a week and without exception they
were all hauled by diesels.


Is that perhaps because the GOBLIN hasn't been electrified yet....??


Anna Noyd-Dryver

On Fri, 10 Feb 2017 12:02:15 -0000 (UTC)
Anna Noyd-Dryver wrote:
wrote:
On Thu, 9 Feb 2017 16:37:46 -0000 (UTC)
Recliner wrote:
wrote:
On Thu, 9 Feb 2017 16:04:47 -0000 (UTC)
Recliner wrote:
wrote:
The vast majority of freight is hauled by class 66 and 70 diesels and
the
main electric freight loco the class 92 can run off 3rd rail anyway.

The main electric freight loco is the class 90. Class 92s are little used.

You sure about that? I thought the 90 was a passenger loco that only
occasionally did light freight because its built for high speed, not
pulling
power.

When did you last see a class 92 hauling anything? Most electric freight
are hauled by class 90s.

I've never seen either on the NLL tbh. When I used to get the ELL from
highbury I saw maybe 1 freight train a week and without exception they
were all hauled by diesels.


Is that perhaps because the GOBLIN hasn't been electrified yet....??

FFS, its like talking to geese.

--
Spud

Graeme Wall wrote:
On 10/02/2017 09:54, d wrote:
On Thu, 09 Feb 2017 19:42:06 +0000
Charles Ellson wrote:
On Thu, 9 Feb 2017 16:37:46 -0000 (UTC), Recliner
wrote:

wrote:
On Thu, 9 Feb 2017 16:04:47 -0000 (UTC)
Recliner wrote:
wrote:
The vast majority of freight is hauled by class 66 and 70 diesels and the
main electric freight loco the class 92 can run off 3rd rail anyway.

The main electric freight loco is the class 90. Class 92s are little used.

You sure about that? I thought the 90 was a passenger loco that only
occasionally did light freight because its built for high speed, not
pulling
power.

When did you last see a class 92 hauling anything? Most electric freight
are hauled by class 90s.

Class 92s tend to be seen with Channel Tunnel traffic, there is no
current reason for them to be preferred over straight 25kV locos away
from such traffic.

So there's no freight on southern region then?

Al diesel hauled round here, which is why they are discussing the
"electric spine" running 25kV from Reading to Southampton.



The problem with electric freight on 3rd rail is that the current drawn to
move a competitive-sized freight at a competitive speed, is very close to
the current at which the circuit breakers trip.


Anna Noyd-Dryver