Speed limits under semaphore signalling

What is or was the highest line speed ever allowed under semaphore signalling? Presumably nothing higher than 90 or 100mph, officially? (The Midland Main Line comes to mind, for some reason.) Are there any high-speed sections of line with sempaphore signalling today?

Was/is the existence of semaphore rather than colour light signalling a criteria in setting line speed? I guess it gets harder to spot such signals the faster you go.

Deltics ran at 100 for years on the ECML under semaphores (with AWS eventually if not everywhere at the start). AFAIK all higher speed lines were equipped with MAS.

I'm not aware that semaphores as such restricted speed; there were plenty of cases where distant signals were resited to allow increased braking distance, they were often made colour lights but I assume that was for convenience.

Or too long a pull.

Pre-war, didn't the LNER run the non-stop expresses with double blocking, so increasing the effective braking distance.
Pat

Dunfanaghy Rd said:

Pre-war, didn't the LNER run the non-stop expresses with double blocking, so increasing the effective braking distance.
Pat

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I'm fairly certain that was also done on the WCML north of Crewe during the time of accelerated timings with double headed 50s.

Mallard attained the Steam speed record of 126 mph under Semaphores.

Ploughman said:

Mallard attained the Steam speed record of 126 mph under Semaphores.

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On a line passed only for 90 though.

30907 said:

Deltics ran at 100 for years on the ECML under semaphores (with AWS eventually if not everywhere at the start). AFAIK all higher speed lines were equipped with MAS.

I'm not aware that semaphores as such restricted speed; there were plenty of cases where distant signals were resited to allow increased braking distance, they were often made colour lights but I assume that was for convenience.

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The LMS in particular had a policy between the Grouping and WW2 of replacing 'remote' distant semaphore signals (ie those out in the countryside rather than at stations or junctions) with two-aspect colour-light signals. There were several reasons for this. Firstly in the more frequent fogs/smogs of the 1930s (due to the greater use of coal) the glow of a powerful colour-light was much more obvious in the fog, and this was safer. Secondly it eliminated the need for sending out a 'fogman' - probably a permanent-way man on overtime - to do an unpleasant and potentially dangerous task of putting detonators on and off the line depending on the aspect of the signal. Thirdly it eliminated the expense of maintaining a mile or more of wire running over many pulleys between the signal box and the signal. It also made things easier for the signalman, although I suspect that was the least of the LMS's objectives!

At St Albans South we're fortunate enough to have some of the paperwork relating to the replacement of the two down distant signals in December 1938. The opportunity was also taken to move the distants further away from the box - we assume this was to accommodate higher train speeds.
The slow line distant was a three-aspect: yellow-green or double yellow for the advance warning of the junction from down Slow to Down Fast at St Albans South being in use. Very interestingly this latter feature was deleted in a completely different hand to the original writing on the form; we wonder if this was a consequence of the accident in September 1945 at Bourne End on the WCML where a train derailed on a similar crossover with significant loss of life. The subsequent inquiry drew adverse comment on the use of a double-yellow signal in such circumstances, and their use was discontinued soon afterwards.

Colour light distants but the Hope Valley line is 90 mph with mostly semaphore running signals.

Shimbleshanks said:

What is or was the highest line speed ever allowed under semaphore signalling? Presumably nothing higher than 90 or 100mph, officially? (The Midland Main Line comes to mind, for some reason.) Are there any high-speed sections of line with sempaphore signalling today?

Was/is the existence of semaphore rather than colour light signalling a criteria in setting line speed? I guess it gets harder to spot such signals the faster you go.

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Limited to 100mph I believe. The Midland hasn't had semaphores since the completion of Leicester re-signaling in 1989ish, and although it had HSTs by then there was no running over 100mph.

I believe that in semaphore days, Reading to Exeter via the Berks and Hants had a maximum speed limit of 90 mph.

In steam days only a relatively small number of locomotives had speedometers. It was left to the driver to estimate speed. I doubt any locos had a speedometer during 'railway race to north' hence tales of derring do.

LowLevel said:

Colour light distants but the Hope Valley line is 90 mph with mostly semaphore running signals.

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Dunblane to Hilton Junction near Perth is the same but with 100 mph sections as well.

matacaster said:

In steam days only a relatively small number of locomotives had speedometers. It was left to the driver to estimate speed. I doubt any locos had a speedometer during 'railway race to north' hence tales of derring do.

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More recently, even, the Class 506 DC EMUs for Manchester-Hadfield (withdrawn in 1984 after conversion of the line to AC) did not have speedometers either, however to get back to the topic the only semaphores they were likely to encounter were as they went past the goods lines at Guide Bridge East Junction.

No mechanical signalling above 100mph due to signal sighting according to the standards.

As a sub-topic, what about highest speeds allowed with semaphore distant signals? I'm fairly sure that, in the 1970s, some stretches of the SR Faversham to Dover line were cleared for 90 mph even though there were wire-operated semaphore distants at some locations (Kearsney, Adisham, Selling?).

On the WR in the 1950s, before the diesels arrived, there was no speed limit on the main lines. From the summer 1957 WTTs:

"Until further notice, the maximum permissible speed of trains on the Down and Up Main Lines between the following points will be as high as may be necessary, subject to the observance of all permanent and temporary speed restrictions.
I believe this was a reinstatement of the pre-war situation.

GEML had some 95mph running through Norfolk under semaphores pre-1986.

4069 said:

On the WR in the 1950s, before the diesels arrived, there was no speed limit on the main lines. From the summer 1957 WTTs:

"Until further notice, the maximum permissible speed of trains on the Down and Up Main Lines between the following points will be as high as may be necessary, subject to the observance of all permanent and temporary speed restrictions.

PADDINGTON TO PLYMOUTH VIA LAVINGTON
READING TO BRENT KNOLL VIA SWINDON AND BRISTOL
DIDCOT TO YARNTON
PADDINGTON TO ARDLEY"
​

I believe this was a reinstatement of the pre-war situation.

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This of course seems more dramatic than it really was!

The most widely used steam locos on passenger service on the Western were the Halls of various vintages. These had Stephenson's link valve gear which, although it gave good acceleration, rather throttled the engines much above 75 to 80mph. Castles and Kings were good for another 10mph or so but with the long trains of the time also mostly ran at around 75 to 80 mph.

90mph was the exception rather than the rule!