Tripcock Testing

[d7666]

Moved from the SSR Resignalling Thread as this was more general than SSR-specific - Tom

Feb 6, 2023 9:47:44 GMT Tom said:

As an aside, and a matter of historical record, the curent locations of Tripcock Testers on the SSR network is as follows:

District Line
Acton Town - all platforms
Barons Court - WB District
Earl's Court - all platforms
East Ham - EB
Upminster Bridge - both platforms

Metropolitan Line
Finchley Road - both Met platforms
Harrow on the Hill - platforms 1, 3, 4, 5, & 6.
Ruislip - WB
Moor Park - NB local
Chalfont and Latimer - bay platform (2x Testers both now out of use but not formally decommissioned)
Amersham - Platform 2 (NB) and Platform 3 (SB)

Digressing, I must look into what the present arrangements are a Finsbury Park main line on the approaches to Northern City into Moorgate. There were once some form of tripcock tester for 313s and presumably 717s on the relevant Up roads at the north end of the passenger platforms.

I have lost track of where they are with ETCS from Drayton Park; I think it ought to be operational now, but despite a google search I can't seem to find any confirmation it actually is.

Having thought about it, I have no idea how tripcock tester pass or fail was indicated to 313/717 drivers.

Nor how it is indicated on Merseyside either (assuming they test).

[Tom]

I understand the arrangement at Finsbury Park was that the signal could not clear towards Drayton Park if the train had failed the tripcock test.

[joshua]

How many of the Tripcock Testers will stay once the 4LM is complete and where will they be on the SSR network? Will Chiltern Railways keep there tripcocks?

[t697]

The LUL area used by Chiltern trains will retain trainstops for these 'alien' trains and the Chiltern trains will retain tripcocks to continue to provide the Train Protection scheme.

[rincew1nd]

Feb 6, 2023 21:37:18 GMT Tom said:

I understand the arrangement at Finsbury Park was that the signal could not clear towards Drayton Park if the train had failed the tripcock test.

It's odd that this is what I'd expect, yet the LU standard allows the signal to clear.

[Tom]

Feb 6, 2023 22:46:48 GMT joshua said:

How many of the Tripcock Testers will stay once the 4LM is complete and where will they be on the SSR network? Will Chiltern Railways keep there tripcocks?

I'm not sure about the totals but Earl's Court and Harrow on the Hill are certainly being retained for the considerable future.

[Tom]

Feb 7, 2023 22:00:10 GMT rincew1nd said:

[It's odd that this is what I'd expect, yet the LU standard allows the signal to clear.

The LU method makes sense when you think that it's an all-tripcock railway. In the Finsbury Park example the train is about to enter the tripcock area from a TPWS area - so before allowed to get near the 'new' train protection system it must be proved to be functional.

A similar principle is used downstairs at Finsbury Park for transfers of stock from the ATP-fitted Victoria line to the Tripcock-equipped Piccadilly line - unless the Tripcock is proved in gauge, you can't cross over.