Matt Wheeler wrote:
SNIP!

Towards Amersham, from Aylesbury, the trains enter LUL track at,
presumably, 60mph at "Mantles Wood Junction".
Where is the first LUL signal with trip after the junction and before
Amersham station, presumably before the siding line into the main
london bound platform at Amersham... but how close, as the trains will
still be travelling at some speed at that point.


Yep. Signal JW1. Depending on how you drive, you would be doing
anywhere between 60 and about 40 there. You would always be slowing
down for the platform at Amersham, because you are either calling at
the station, or slowing down for the Tripcock Test in the in the
platform at Amersham (its a white light by the side of the signal.
There is a device that looks like a pedal on the track, and you must
pass over that at no more than 10mph. If the white light goes out, the
test is passed, and you can proceed normally, if the light stays on,
the test is failed and you dont go any further) There was a tripcock
tester on exiting Amersham towards Aylesbury on platform 3, where the
vast majority of Chiltern services are routed. This has been removed,
and there now sits a 15mph speed limit through the station. Ive not
been through platform 2 exiting the LUL since the tripcock tester on 3
has been removed, though im fairly certain that the tester is still
there.

The effects of dangling tripcocks striking raised trainstops doesnt
seem to be a problem. Trains have been working like this for years, and
the world is still spinning. Fair enough, its got people talking on
here about it, and some of the comments have been interesting, but the
system works, and LUL, who dont change anything (there are still "off"
indicators at a lot of Met stations!) unless they really have to, arent
going to change something that isnt causing them a problem any time
soon.

As for the maximum speed limit on the LUL, well, there is a very grey
area at Amersham. There is a 70mph speed limit sign between Amersham
station and the Network Rail boundry, beyond the electrified track.
Now im told that the maximum speed anywhere on the LUL is 60mph. Ive
never seen this written down, but ive been told many times by many
different people that it is. But this 70mph sign exists. Can trains do
70mph there, or is this 60mph limit real? I for one keep on acclerating
past 60mph.

On 18 Jul 2005 20:17:11 -0700 someone who may be "Minna Daisuki
Katamari Damacy" wrote this:-

The effects of dangling tripcocks striking raised trainstops doesnt
seem to be a problem.

About 100 years ago the problem of striking raised trainstops at
speed led to the failure of a number of devices based on the method.
The NER persisted, but only by using a ramp a bit like the GWR ramp
to give some of the indications on their Fog Signalling Apparatus.
Since then metallurgy has progressed, but there is only so much that
can be done about fatigue.

Striking a trainstop occasionally at high speed is very different to
striking them regularly at high speed. One of the reasons there are
tripcock testers is to ensure that the arm has not broken off.


--
David Hansen, Edinburgh | PGP email preferred-key number F566DA0E
I will always explain revoked keys, unless the UK government
prevents me by using the RIP Act 2000.

David Hansen wrote:
snip
Striking a trainstop occasionally at high speed is very different to
striking them regularly at high speed. One of the reasons there are
tripcock testers is to ensure that the arm has not broken off.

I'd put that differently. The tripcock tester is there to ensure that
1) the train has a tripcock set
and
2) that the tripcock is to gauge.


--
Cheers for now,

John from Harrow, Middx

remove spamnocars to reply

Do people have to have the last word on EVERYTHING in here?

He said ONE of the reasons the tripcock tester is there is to ensure
that the arm has not broken off.

ONE of the reasons. Not ALL of the reasons!

No need to try and correct everything that is posted on here. Credit
people with a little intellegence, please!

"Minna Daisuki Katamari Damacy" wrote in
message ups.com...


SNIP!


As for the maximum speed limit on the LUL, well, there is a very grey
area at Amersham. There is a 70mph speed limit sign between Amersham
station and the Network Rail boundry, beyond the electrified track.
Now im told that the maximum speed anywhere on the LUL is 60mph. Ive
never seen this written down, but ive been told many times by many
different people that it is. But this 70mph sign exists. Can trains do
70mph there, or is this 60mph limit real? I for one keep on acclerating
past 60mph.


If you are lucky enough to actually get a unit capable of getting above 60
before Mantles Wood! Having to clear the 15mph "ESR" doesn't make it any
easier either.

Roger

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All opinions expressed are my own and do not necessarily reflect the views
or policies of my employer.

True. But its always good to try! ;o)
I usually manage to be able to creep over the 70mph barrier just as the
radio goes back to area 88.