Complex block sections

[The Stationmaster]

4 minutes ago, ReTyerd Signalman said:

I guess before Mr Tyer invented his tablet system there was nothing better.  After that many railways just didn’t want to spend money!

Best head back to signalling school - there was a very obvious reason for doing it ona line line worked by TS&T very many years after Mr Tyer and other invented their various single line instruments.  If you had a set of Mr Tyer's (or others') instruments you would obviously not need TS&T working

[Michael Hodgson]

36 minutes ago, ReTyerd Signalman said:

I guess before Mr Tyer invented his tablet system there was nothing better.  After that many railways just didn’t want to spend money!

 

46 minutes ago, The Stationmaster said:

 

Anyway why would ordinary double block instruments be used with TS & T working as they do absolutely nothing to prevent trains being signalled in opposite directions overa. single line?

I see it as arising from the Board of Trade's Requirements and Recommendations which came in after the pre-telegraph accidents that were happening under Time Interval on double lines and necessitated the Regulation of Railways Acts as services became more frequent in the second half of Victorian's reign.

On a double line, all trains are going the same way, so you're not worried about head-ons, only the risk of overtaking an earlier train, so all you need is ordinary block.  The risk on a single line is obvious and intuitively nastier.  With One Engine in Steam the staff alone is enough protection against both head-ons and against two in a bed in the same direction.   Possession of the staff is enough.

 

With TS&T you still won't run the risk of head-ons but you do bring back the risk of two in section in the same direction unless you add block working (hence the instruments)  as that stops you letting a second train enter in the same direction until the first has cleared out.

 

Ordinary block working as used on a double line wasn't seen as adequate to protect against opposing trains on a single line and I think that's why the Board of Trade requirements listed TS&T combined with block working as an acceptable method of working. 

 

Electric Token was just a more sophisticated way of applying the original Train Staff concept, by enabling the Train Staff to be moved to either end on demand and it also gave you the co-operative offer/acceptance process that you don't have with simple Train Staff without telegraphy.

 

 

[RailWest]

I'm bemused how this thread seems to have drifted so far from the original question and almost gone off into fantasy land...:-)

 

Let us not forget that many early railways ran many miles of single-line track by block instruments only, a well-known example being the Somerset & Dorset. Even after the Foxcote disaster the BoT does not appear to have recommended TS&T (ETT not yet being available) and only made a 'recommendation' in 1886 after the second Binegar accident, by which time the S&DJR had started to use ETT anyway (albeit in a small way).

 

Block working with TS&T did not require block instruments of necessity, you could for example simply use bell block, as was the case between Highbridge and Burnham right up until closure in the early 1960s. Both the S&D and GWR had some sections - admittedly very short - that remained worked by instruments only (no staff). Light railways often used used telephone block with TS&T, as did (and may still do) some 'heritage' lines - indeed I worked TS&T on the WSR for several years by telephone and (fortunately!) don't recall any incidents :-) It is true of course that TS&T does have it weaknesses and can fail if not worked properly, as was witnessed a few years ago on one well-known line in the south-east ...... one reason why, in a scheme with which I am  involved at the moment in the heritage sector, we have banned it as method of working.

 

Although 'bog standard' double-line block instruments would not be appropriate for use on single-lines, variants of them certainly did get used. The L&SWR used a 'single-line version' of their standard Preece 2-position blocks on many of their TS&T branches. Even in the late 1960s the rationalised IoW line used modified standard SR 3-wire 3-position instruments to provide Tokenless Block working, but you would be hard pressed to tell them from the 'normal' instruments just from a glance at them.

 

 

[The Stationmaster]

18 hours ago, Michael Hodgson said:

 

I see it as arising from the Board of Trade's Requirements and Recommendations which came in after the pre-telegraph accidents that were happening under Time Interval on double lines and necessitated the Regulation of Railways Acts as services became more frequent in the second half of Victorian's reign.

On a double line, all trains are going the same way, so you're not worried about head-ons, only the risk of overtaking an earlier train, so all you need is ordinary block.  The risk on a single line is obvious and intuitively nastier.  With One Engine in Steam the staff alone is enough protection against both head-ons and against two in a bed in the same direction.   Possession of the staff is enough.

 

With TS&T you still won't run the risk of head-ons but you do bring back the risk of two in section in the same direction unless you add block working (hence the instruments)  as that stops you letting a second train enter in the same direction until the first has cleared out.

 

Ordinary block working as used on a double line wasn't seen as adequate to protect against opposing trains on a single line and I think that's why the Board of Trade requirements listed TS&T combined with block working as an acceptable method of working. 

 

Electric Token was just a more sophisticated way of applying the original Train Staff concept, by enabling the Train Staff to be moved to either end on demand and it also gave you the co-operative offer/acceptance process that you don't have with simple Train Staff without telegraphy.

 

 

Exactly so.  the use off irdnary block instruments imposes the legally required space interval between successive trains.  And it was no doubt the simplest answer to use readily available ordinary double line instruments rather than conjure up something else.  I don't know about any other issues but the 1950 edition of 'the Requirements' states explicitly in the section regarding TS&T working that 'The absolute block system with suitable block instruments must be used to ensure a proper space interval between trains.'

 

That is exactly how the Central Wales Line was worked when it was rationalised down to fairly basic status with TS&T working (that, of course, being prior to it being converted to NST(R) operation).  interestingly this method of woking was included in the GWR Block Regulations but did not appear in the WR version of the 1960 Block Regulations which suggests that by then its use in the Region was either extremely limited or non-existent.  It was  however in the 1960 Regulations applicable to all the other Regions and it carried over into the 1972 version of the Block Regulations thath applied to all Regions which indicates that there was sufficient examples of it in use to merit its inclusion in the book.