Zoe

It is listed as Paddington - Hayes stage 1C in the SRS archive catalogue although the notice itself is not a available for download. Although the 1964 notice regarding the West Drayton area does refer to it as the final stage of the Reading - Hayes MAS scheme. What I'm still not sure about though is if the plan in the 1950s could have been to install MAS all the way through to Paddington but have this controlled from the existing boxes (considering power boxes were ruled out at this time except where they could be justified by exceptionally good financial return) and if this later changed when as you say there were changes to operational practice in the 1960s. Would also be interesting to know what the original proposals (referred to in the document as involving several power boxes and considered too costly) would have been but I doubt that information survives anywhere today.

I recently found this https://www.jonroma.net/media/signaling/articles/irse/Some Signalling Developments on the Western Region. Tyler%2C J. F. H. IRSE Proceedings. 1954.pdf which gives some details of the1950s schemes, starting on page 106. Considering the first part of the Paddington - Hayes scheme was introduced in 1953 but Paddington station was not resignalled until 1967 I have often wondered if the 1967 Old Oak Common panel was part of the original plan. The above document says that initial proposals involving a number of power boxes were ruled out on cost grounds and so it was decided to retain the existing boxes for the MAS (except where exceptionally good financial return was predicted). Even the panel that was installed at West Ealing in 1955 could not be justified in its own right, but was used as a testing ground for a larger scheme elsewhere. So it seems there was a change of plan which explains why after the initial push eastwards from Southall to reach Acton Middle in 1955, progress was slow with the MAS not reaching Paddington itself until 1967. I wonder if a panel taking over at least the Paddington Boxes and Westbourne bridge would have been justified had the plans not changed.

The box instructions for Barmouth South (again available from the SRS website at https://www.s-r-s.org.uk/html/gwu/S3224.htm) show: This would seem logical for the situation where Truro East had a full clearing point available but did not have line clear through to the next box east. Truro West's Distant would then effectively act as an additional fixed distant for East giving 922 yards to Truro East Up Main Home (This is however still less than the 1000 yards shown in the book for a falling gradient but the severe 15 mph PROS through the Up Platform may have been taken in account). This would then avoid the seemingly unsatisfactory situation of a West having to maintain the Up Home at danger and the driver seeing it after having previously not been cautioned at Penwithers Junction. The problem here though is if regulation 4A was used for the purposes of allowing East to accept a train without having the full clearing point available (which was suggested above would have been the case if modified clearing points were not used). This I believe would require the train to be cautioned at Truro West and I can't see any way of doing this if the driver sees a cleared distant at Penwithers Junction (West having accepted under regulation 4). Unless of course West did indeed maintain their Up Home at danger until the driver saw it after emerging from the tunnel but I feel very uncomfortable about that situation.

This doesn't seem ideal at all. If after seeing Penwithers Junction Up Distant cleared, the driver assumes that they have the road into the platform at Truro then wouldn't the first reaction after emerging from the tunnel be to slam on the emergency brake after seeing the Truro West Up Home at danger even if it does then get cleared?

Thanks for the explanation, I was a little uneasy about the fixed distant not always meaning to expect Truro West's Up Home to always be at danger but driver knowledge must have covered that so if the driver saw Penwithers Junction Up Distant cleared then they would know they had the road into the platform. Regarding regulation 4A between the two boxes, the situation on the down line is quite clear in the Truro East would have to maintain their distant at caution if West only accepted under 4A but what would regulation 4A achieve on the Up, considering that West's Distant was fixed at caution, it would stay that way even if East accepted under regulation 4. Incidentally, after Probus closed Grampound Road remained open through to 1972 (presumably just to break the very long section to Burngullow after all the sidings were taken out of use in the 1960s).

That was certainly the case at Taunton West Station, the box instructions (available from the SRS website at https://www.s-r-s.org.uk/html/gwe/S732.htm) show that Taunton West Junction's Up distants were maintained at caution when that box was out of circuit with regulation 4A then not applying.

What I'm still not sure about though is why Penwithers Junction had a worked distant on the Up Main at all. If all trains were accepted by Truro West under regulation 4A then it could never have been cleared. Looking at the diagram for Truro East, it shows a worked distant on the Down Main which could never have been be cleared if Truro West had to accept under regulation 4A unless the 30 mph PSR through the platforms could have avoided this situation but it seems that the platforms were not long enough. It would appear then that both Penwithers Junction and Truro East had worked distants which could never have been cleared.

You can find these in the relevant Service Timetables. Michael Clemens has a full set of these for September 1949 at https://www.michaelclemensrailways.co.uk/?atk=592 although these are of course from just after the GWR became the WR. You will find the information in the latter pages, after the end of the main timetables. There are also some older timetables available on the same site at https://www.michaelclemensrailways.co.uk/?atk=625

I have just been looking at the George Pryer diagrams for the Truro area and have noticed that Truro West only had one distant arm for the up line (fixed at caution on the same post as the Penwithers Junction Up section signal). This however is shown to have been at a distance of 590 yards in rear of Truro West box, with the Up Main Home at 189 yards in rear leaving only 401 yards from distant to home. This would suggest that regulation 4A would have been required for every train but that would make it pointless for Penwithers Junction to have a worked Up Main Distant at all if it could never be cleared. There were also two other stop signals in rear of the section signal which could have had distant arms below them to more braking distance but for some reason did not. There does not appear to have been a speed restriction at Penwithers Junction or a severe rising gradient towards Truro so would the driver have been expected to have known to expect Truro West box Up Home to be at danger even though the fixed distant would have been located after the point at which they would have needed to start braking? There was I believe a speed limit through Truro station but the braking point for that would have been later.

On the subject of feathers, this video https://www.youtube.com/watch?v=NmPzB0qTy4M (filmed in 1962 just before the MAS reached Old Oak Common) shows feathers above Ladbroke Grove's Down Main Home and Down Relief Home signals at 1:01. I was informed elsewhere these were was added so that the original searchlight heads for the diverging routes could be removed and converted for use in the MAS.

Searchlights were installed all the way to Southall by the GWR in the 1930s. I believe these were converted for use in the 1950s MAS scheme.

Looking at this video of Hanwell in the 1970s https://www.youtube.com/watch?v=vmiqdTadyRw it seems that some MAS searchlights were still in use. I believe the Hanwell signals would have been installed in 1953 as part of the first MAS installation from Hayes to Hanwell and in 1955 when the MAS was extended to Acton.

Speed restrictions were published in the service timetables, there is a full set of 1949 STTs available on Michael Clemens' site: http://www.michaelclemensrailways.co.uk/?atk=592 Section 3 covers the route, you will find the speed restrictions for your section of line on page 158. Note that only specific locations were subject to a speed restriction, elsewhere a 75 mph limit applied.

I've just gone back over some discussions a few years back elsewhere on the issue and on two separate occasions it was said that when the ORR were in the area following the crossing fatality the usage of platform 4 was picked up on and that it was then suggested that it didn't use that platform. It seems that the issue was due to easy access to the doors on the unplatformed side of the train. It may well be that the ORR informed the TOC of this observation and the TOC then requested the move to platform 1.

The WTT (available on the NR website) shows 5C99 departing Penzance at 0915 on Mondays and 0822 on Tuesdays to Saturdays.