Locomotive speedometers

[Rescars]

Following on from the Milton accident thread and the discussion about locomotive speedometers, does anyone know if any company fitted many of these prior to nationalisation? Campbell--Cornwell gives details of Stroudley's speed indicator which was patented in 1875 and apparently fitted widely during his tenure on the LBSC. I understand Gladstone is still so equipped. Did the Brighton continue with this and/or did any other company follow suit or do something similar?

 

[Taunton]

I understood the LNER was the only Big Four company to fit them to express locos. Bulleid may have done the same at the end with his Pacifics.

Incidentally, the road transport industry was the same at the time for lorries and buses.

 

[Richard Scott]

I understood the LNER was the only Big Four company to fit them to express locos. Bulleid may have done the same at the end with his Pacifics.

Incidentally, the road transport industry was the same at the time for lorries and buses.

I thought GWR passenger locos also had them?

 

[Gloster]

I thought GWR passenger locos also had them?

To repeat briefly an item I posted in the Milton Accident thread: ten Castles built in 1948 definitely didn’t have speedometers from building and the next ten from the following year probably didn’t. They had them fitted from 1950 to 1954.

 

[pokemonsuper9]

Did trains really run around with the only clue to speed being the driver's best guess?
I can only imagine a lot of speeding happened, a few years ago a TPE 802 made it to 145mph (on probably the worst track for trying to guess a speed given the featureless nothing) and that has a speedometer staring right at the driver.

 

[Bevan Price]

Did trains really run around with the only clue to speed being the driver's best guess?
I can only imagine a lot of speeding happened, a few years ago a TPE 802 made it to 145mph (on probably the worst track for trying to guess a speed given the featureless nothing) and that has a speedometer staring right at the driver.

Yes. I was told that even "Mallard" had no speedo when it made its record run. Also, some permanent speed limits were lower than really necessary, on the assumption that some drivers were likely to exceed those limits.

And some speedometers were not always reliable - for example ageing Class 47s in their final years on the North Wales Coast - on one train, a Class 47/7 briefly reached 105 mph (measured by GPS) when the line limit was still 75 mph; another was "failed" at Stafford with a faulty speedo.

 

[Rescars]

I thought GWR passenger locos also had them?

Had the City of Truro been equipped perhaps there would have been less dispute about the record run in 1904. I wonder if the absence of speedometers encouraged furious (hairaising!) driving during the Races to the North in 1888 and 1895.

 

[thesignalman]

Did trains really run around with the only clue to speed being the driver's best guess?

Yes, that was indeed the case - and speed limits themselves were not fully defined until (in most cases) 1960. For example, the WR used to state "the maximum permissible speed of train on the Down and Up Main lines between ... and ... will be as high as may be necessary, subject to the observance of all permanent and temporary speed restrictions".

In reality, train timings were slack compared with how they are these days so trains did, in fact, usually run well below the permitted speeds. Typically, express trains would be timed to run at around 70 mph (nearer 60 on the WR!) so good timekeeping was easily achieved without rushing.

It is interesting to note that with the diesel era in place, freight train maximum speeds for different classes were generally reduced by about 5 mph and my suspicions are that this came about largely because trains were running faster once speedometers were provided.

John

 

[45Fox]

Did trains really run around with the only clue to speed being the driver's best guess?

As already stated, they did.

I think I'm correct in saying that the last main line stock operated by British Rail that didn't have speedometers were the Southern Region class 405 (4 SUB) EMUs, finally withdrawn in 1983.

 

[hexagon789]

Did trains really run around with the only clue to speed being the driver's best guess?

Paris ran Metro trains without speedos as late as 1983 - the Sprague-Thomsons never had them.

In fact the only "instrument" the driver had was the air brake guage.

As already stated, they did.

I think I'm correct in saying that the last main line stock operated by British Rail that didn't have speedometers were the Southern Region class 405 (4 SUB) EMUs, finally withdrawn in 1983.

Amusingly same year as Paris withdrew its Sprague-Thomsons - see above.

Yes. I was told that even "Mallard" had no speedo when it made its record run.

Thought she had a Flaman speed recorder fitted, but it only went to 120?

Yes, that was indeed the case - and speed limits themselves were not fully defined until (in most cases) 1960. For example, the WR used to state "the maximum permissible speed of train on the Down and Up Main lines between ... and ... will be as high as may be necessary, subject to the observance of all permanent and temporary speed resrestrictions"

The LNER began defining all its restrictions formally in the mid/late-30s and BR adopted this system.

The WR postwar instituted an 80mph ceiling, except for certain Express trains where 85mph was authorised in certain locations. In 1955 to 1960, it then went back to the arrangement you describe.

A 90mph ceiling was then imposed in 1960.

 

[Taunton]

The irony was that the loco crew were only guessing at their speed, whereas amateur stopwatch train timers back in the train, initially Charles Rous-Martin (on the City of Truro run), later Cecil J Allen and O S Nock, and others, were claiming speeds to the nearest 1 mph and publishing them regularly in magazines.

Indeed, Sir Arthur Conan Doyle, no mean rail enthusiast himself, has Sherlock Holmes and Watson in "Silver Blaze" discussing train timing methods, published in 1892. Holmes has, of course, timed their train to the nearest HALF mile per hour! Page 1 in the extract here:

We had left Reading far behind us before he thrust the last one of them under the seat, and offered me his cigar-case. “We are going well,” said he, looking out the window and glancing at his watch. “Our rate at present is fifty-three and a half miles an hour.” “I have not observed the quarter-mile posts,” said I. “Nor have I. But the telegraph posts upon this line are sixty yards apart, and the calculation is a simple one.

https://sherlock-holm.es/stories/pdf/a4/1-sided/silv.pdf

 

[pokemonsuper9]

The irony was that the loco crew were only guessing at their speed, whereas amateur stopwatch train timers back in the train, initially Charles Rous-Martin (on the City of Truro run), later Cecil J Allen and O S Nock, and others, were claiming speeds to the nearest 1 mph and publishing them regularly in magazines.

Indeed, Sir Arthur Conan Doyle, no mean rail enthusiast himself, has Sherlock Holmes and Watson in "Silver Blaze" discussing train timing methods, published in 1892. Holmes has, of course, timed their train to the nearest HALF mile per hour! Page 1 in the extract here:

We had left Reading far behind us before he thrust the last one of them under the seat, and offered me his cigar-case. “We are going well,” said he, looking out the window and glancing at his watch. “Our rate at present is fifty-three and a half miles an hour.” “I have not observed the quarter-mile posts,” said I. “Nor have I. But the telegraph posts upon this line are sixty yards apart, and the calculation is a simple one.

https://sherlock-holm.es/stories/pdf/a4/1-sided/silv.pdf

I've taken to estimating speeds with a stopwatch and the quarter mile markers recently, since my usual speedometer app was having issues and this is a relatively easy way to do so anyway.

 

[hexagon789]

I've taken to estimating speeds with a stopwatch and the quarter mile markers recently, since my usual speedometer app was having issues and this is a relatively easy way to do so anyway.

Assuming the posts are accurate, many weren't or aren't.

Short or long miles are a thing! (In the railway milepost context that is.)

 

[Gloster]

The irony was that the loco crew were only guessing at their speed, whereas amateur stopwatch train timers back in the train, initially Charles Rous-Martin (on the City of Truro run), later Cecil J Allen and O S Nock, and others, were claiming speeds to the nearest 1 mph and publishing them regularly in magazines.

Indeed, Sir Arthur Conan Doyle, no mean rail enthusiast himself, has Sherlock Holmes and Watson in "Silver Blaze" discussing train timing methods, published in 1892. Holmes has, of course, timed their train to the nearest HALF mile per hour! Page 1 in the extract here:

We had left Reading far behind us before he thrust the last one of them under the seat, and offered me his cigar-case. “We are going well,” said he, looking out the window and glancing at his watch. “Our rate at present is fifty-three and a half miles an hour.” “I have not observed the quarter-mile posts,” said I. “Nor have I. But the telegraph posts upon this line are sixty yards apart, and the calculation is a simple one.

https://sherlock-holm.es/stories/pdf/a4/1-sided/silv.pdf

Conan Doyle was wrong on this. Although telegraph posts were at roughly standard intervals, the distance could vary, both between companies, routes and along the same line. Unless Holmes knew exactly the average distance between poles on the section of line they were using, he could never calculate the train’s speed to the nearest half-mile an hour. As he in A Study in Scarlet described the brain as a ‘little empty attic’ that should not be filled with ‘lumber of every sort’, one feels it is unlikely that he would fill it with a comprehensive knowledge of the distances between telegraph poles on the nation’s railways.

 

[ThirteenArches]

a Class 47/7 briefly reached 105 mph (measured by GPS)

Note that GPS speedometers are nothing like infallible. They depend on visibility of satellites to the receiver, and behaviour when coverage is inadequate depends on the whim of whoever designed the software. My GPS indicator recently told me I was travelling at 34mph. I suspected this was inaccurate, as I was waiting at a red traffic light at the time. It had obviously held whatever was the last valid reading it got.

 

[jfollows]

As already stated, they did.

I think I'm correct in saying that the last main line stock operated by British Rail that didn't have speedometers were the Southern Region class 405 (4 SUB) EMUs, finally withdrawn in 1983.

The Class 506 DC EMUs ran until 7 December 1984 (until the line to Hadfield was re-electrified at 25kV AC) and, as I noted in the other thread, didn’t have speedometers either.

 

[Rescars]

Did dynamometer cars record speed accurately as well as all the other measurements taken?

For those without sophisticated equipment, the 1960 General Appendix contains a table to calculate speeds using quarter mile posts. The top speed quoted is 90mph. At the bottom of the table we are advised that 5 minutes between quarter mile posts represents 3mph. A separate calculation is given for every mph up to 33mph. Accurate timings of unfitted freight were possible!

 

[Taunton]

The standard way to measure train speed in old times was by a specific instrument in the Dynamometer Car. a special engineering department test carriage that would be occasionally added behind the locomotive; each major railway generally had just one. The LNER one was included in Mallard's historic speed run of 1938, they knew what they were trying for. It had an additional wheel which was dropped onto the rail. Cecil J Allen was invited in for a few trips, and compared it to his stopwatch methods; he wrote it was "so amazingly accurate" that it was a waste of time to use his normal way; I wonder if it actually showed up his through-the-window style of observing mileposts was not as accurate as he portrayed. It had a very large dial in the centre of the car.

The Dynamometer Car recorded a whole series of engineering parameters on various instruments, many imported (as the speedometer was, a number by Flaman of France; its internal power was clockwork, so it had to be wound up first), as there really wasn't any British demand for them. It measured drawbar pull and other values, plotted these measurements on large paper rolls, and had desks for the engineers. In best railway management tradition it also had a kitchen, a separate dining table, and a steward to provide immaculate service to all!

 

[hexagon789]

Note that GPS speedometers are nothing like infallible. They depend on visibility of satellites to the receiver, and behaviour when coverage is inadequate depends on the whim of whoever designed the software. My GPS indicator recently told me I was travelling at 34mph. I suspected this was inaccurate, as I was waiting at a red traffic light at the time. It had obviously held whatever was the last valid reading it got.

Though 47s have been recorded at higher speeds than even 105mph, so it's not necessarily an inaccurate reading even allowing for the fallibility of GPS recordings.

 

[Rescars]

In best railway management tradition it also had a kitchen, a separate dining table, and a steward to provide immaculate service to all!

But not quite so sumptuous if you were one of the folk taking measurements whilst cooped up in an indicator shelter strapped to the front buffer beam with the smokebox door for company!

 

[45Fox]

The Class 506 DC EMUs ran until 7 December 1984 (until the line to Hadfield was re-electrified at 25kV AC) and, as I noted in the other thread, didn’t have speedometers either.

I don't quite know how I managed to forget the 506s, especially as I managed to get a ride on them 3 weeks before they finished!

 

[Magdalia]

The standard way to measure train speed in old times was by a specific instrument in the Dynamometer Car. a special engineering department test carriage that would be occasionally added behind the locomotive; each major railway generally had just one.

British Railways Eastern Region had a new dynamometer car in the early 1950s see here:

Trbwnegs947 Dynamometer Car DB999500

No location for this one thought to have been taken circa 1955. In view is Dynamometer Car DB999500. This was a 1951 Thompson Designed Coach originally numbered DE320041. It became Test Car 2 when transferred to the RTC in the late 60's and was withdrawn after an accident during a slip test in...

www.flickr.com

Cecil J Allen was invited in for a few trips, and compared it to his stopwatch methods; he wrote it was "so amazingly accurate" that it was a waste of time to use his normal way; I wonder if it actually showed up his through-the-window style of observing mileposts was not as accurate as he portrayed.

Observing mileposts from the train isn't very accurate, especially at high speeds. I have experience of doing this, and, a long time ago, I also had experience of assisting manual timekeepers at track athletics meetings. The manual athletics timekeepers started timing when they saw the flash of the starting gun, and stopped as the competitor crossed the finishing line, which was directly in front of them, and few club standard sprinters got up to 20mph, yet there would be some variation in times recorded. In the era when there was a mix of some tracks with electronic timing and some tracks still using manual timing, the track statisticians adjusted manual times up by 0.14 seconds to try to get comparability between the two methods.

The methods used by track athletics timekeepers are more accurate than trying to time two fixed points from a moving train, so I have a fair deal of scepticism about the accuracy of maximum speeds recorded by timing mileposts from a moving train. For myself, I usually only timed the whole mileposts, which had two advantages. Over a longer distance the timing errors are smaller, and, on many routes, the whole mileposts were bigger and easier to see.

Although telegraph posts were at roughly standard intervals, the distance could vary, both between companies, routes and along the same line.

In the days before continuously welded rail, the standard track length was often 60 feet, so timing track joints was an option.

 

[Rescars]

In the days before continuously welded rail, the standard track length was often 60 feet, so timing track joints was an option.

Presumably points could lead to slips though?! Sorry

 

[D6130]

British Railways Eastern Region had a new dynamometer car in the early 1950s see here:

Trbwnegs947 Dynamometer Car DB999500

No location for this one thought to have been taken circa 1955. In view is Dynamometer Car DB999500. This was a 1951 Thompson Designed Coach originally numbered DE320041. It became Test Car 2 when transferred to the RTC in the late 60's and was withdrawn after an accident during a slip test in...

www.flickr.com

Observing mileposts from the train isn't very accurate, especially at high speeds. I have experience of doing this, and, a long time ago, I also had experience of assisting manual timekeepers at track athletics meetings. The manual athletics timekeepers started timing when they saw the flash of the starting gun, and stopped as the competitor crossed the finishing line, which was directly in front of them, and few club standard sprinters got up to 20mph, yet there would be some variation in times recorded. In the era when there was a mix of some tracks with electronic timing and some tracks still using manual timing, the track statisticians adjusted manual times up by 0.14 seconds to try to get comparability between the two methods.

The methods used by track athletics timekeepers are more accurate than trying to time two fixed points from a moving train, so I have a fair deal of scepticism about the accuracy of maximum speeds recorded by timing mileposts from a moving train. For myself, I usually only timed the whole mileposts, which had two advantages. Over a longer distance the timing errors are smaller, and, on many routes, the whole mileposts were bigger and easier to see.


In the days before continuously welded rail, the standard track length was often 60 feet, so timing track joints was an option.

The standard rail length on main lines may have been 60 feet, but many secondary lines had shorter rails....45 feet and even 40 feet being quite common - sometimes with staggered joints - which would make guessing the speed of the train much more difficult. I can think of a couple of places on the Oban and Mallaig lines where such shorter lengths are still in use today.

 

[InkyScrolls]

The standard rail length on main lines may have been 60 feet, but many secondary lines had shorter rails....45 feet and even 40 feet being quite common - sometimes with staggered joints - which would make guessing the speed of the train much more difficult. I can think of a couple of places on the Oban and Mallaig lines where such shorter lengths are still in use today.

The line from Settle Junction to Carnforth is also to this day a mixture of 60' and 30' lengths, with some short sections of CWR.

 

[Trackman]

I don't quite know how I managed to forget the 506s, especially considering I managed to get a ride on them 3 weeks before they finished!

How I found it was when using a train sim, I thought where is the speedo? I looked it up in the manual - there wasn't one!

I travelled on a 506 shortly before the line east of Hadfield was closed. Furthermore, I remember the pretty pictures on the back walls of the 506s.
I only went because I was told to the line was closing but couldn't stay for the final diversions through Woodhead in a couple of days time. I'd never seen a class 76 before, never mind a 506 but I was memorized by looking at the architecture of the DC OHLE at guide bridge looking east.

 

[thesignalman]

The standard rail length on main lines may have been 60 feet, but many secondary lines had shorter rails....45 feet and even 40 feet being quite common - sometimes with staggered joints - which would make guessing the speed of the train much more difficult. I can think of a couple of places on the Oban and Mallaig lines where such shorter lengths are still in use today.

And on the Highland, you can see some from the platform at Brora.

John