Adjusting the clocks

[Ashley Hill]

But that leads to the question: where did all these exchanges get their time signal from?

Could they have got it from the GPO speaking clock? At least from 1936 anyway.

 

[Rescars]

The concept of the time signal being sent out seems a simple concept, until you start to consider the practicalities.

By the time box B had then sent it on to box C, and box C sent it on to box D, and so on, there would presumably have been quite a time delay. Remember that there were a lot of signal boxes around in mechanical days, with even modest stations having boxes at both ends, and intermediate boxes between stations. And at junctions, the signalman might have to repeat it to more than one box. Even if every signalman was stood waiting to start sending it on as soon as he received the first beat, the delay would still build up.

If each box forwarded it at an agreed time, say A to B at 10:00, B to C at 10:01, C to D at 10:02, and so on, then this would surely need to be specified somewhere, presumably in the box instructions, for relief men to know what time it was supposed to be received and sent on at each box.

I am not sure that "speaking instruments" necessarily meant telephones. The "speaking telegraph" was the same as the public telegraph that was used to transmit messages using multiple needles, as opposed to the single-needle block telegraph used for signalling purposes. Signalbox "circuit phones" tended to be fairly local in the area they covered, as with circuits carried on overhead pole routes, the longer the circuit and the more telephones connected to it, the noisier it became. Whereas the telegraph could cover quite long distances, even with multiple receiver stations in circuit.

I have never seen a signalbox with a speaking telegraph, as well as the block telegraphs, but I am sure that there has been mention on here of boxes so equipped so that details of service alterations could be sent out to multiple boxes at once. I suspect that in most places, the telex and the fax replaced the speaking telegraph. However, they wouldn't be much use for transmitting a time signal.

Weren't speaking telegraphs also known as "ting-tang" machines. I'd guess these were to be found alongside block instruments in the era before telephones became commonplace. IIRC these machines survived for a long time for train description purposes on the ECML.

As another way of transmitting accurate time, I am sure I read somewhere that there was a period when, to confirm accurate GMT, a chronometer used to be sent every day from the Greenwich to Dublin by the Irish Mail. Does anyone know any more about this?

 

[Belperpete]

These clocks were the Gent's 'Pulsomatic' system, I think it was called.

I certainly remember seeing pulse clocks with the name "Gents" on them.

== Doublepost prevention - post automatically merged: 30 Mar 2026 ==

Recollection and memories of odd comments from those who had been on the railway for years is that the time signal was sent over the circuit ‘phones by the railway telephone exchange. There were plenty of these exchanges at one time: I believe that, for example, there were exchanges at Westbury, Taunton, Exeter, Newton Abbot and Plymouth.

Weren't these exchanges also the local telephone enquiry offices? I think that the Southern was the odd-man-out in having a centralised enquiry office at Waterloo for the whole region, in most places you phoned your local large (or even local) station if you wanted to know train times, fares, etc.

== Doublepost prevention - post automatically merged: 30 Mar 2026 ==

As another way of transmitting accurate time,

When dial phones came in on BR, it was rare for them to have external (or "level 9") access to the GPO network. I recall that the Southern had an internal number that you could dial to access Post Office TIM.

== Doublepost prevention - post automatically merged: 30 Mar 2026 ==

Could they have got it from the GPO speaking clock? At least from 1936 anyway.

I do not know, but unless there was some local non-railway source, I presume that it was one of two methods. Either each exchange rang somewhere like Paddington, which had got their time from a reliable source, and then they (the exchange) carefully corrected their master clock in the exchange. Or from the first exchange each exchange rang the next down the line. (Or they jumped a few: Paddington told Swindon, which told several including Westbury and Bristol, with the last telling Taunton, etc.; meanwhile Paddington told Exeter, which told Newton Abbot, etc.)

While both of these are possible, they go against the ethos of a time signal distributed universally from a central point at a set time. "Paddington time" wouldn't be Paddington time if the local exchanges were all doing it themselves. And ringing the next exchange down would only work after the introduction of telephones and exchanges. I get the impression that the rule predates the introduction of telephones in most signalboxes (a poster on another thread suggested that this was a war time measure).

Being pendulum clocks, the master pulse clocks were only adjusted by someone who knew what they were doing. However, they were extremely reliable. As I recall, they didn't need winding, they were powered electrically.

 

[Taunton]

But that leads to the question: where did all these exchanges get their time signal from?

If Waterloo was the Master Exchange on the Southern Region they could have opened the window and listened out for Big Ben .

 

[Belperpete]

If Waterloo was the Master Exchange on the Southern Region they could have opened the window and listened out for Big Ben .

The chimes of Big Ben broadcast live on the radio certainly used to be the recognised way of checking clocks and watches in non-railway situations. But of course the railway time signal predates radio.

 

[Bald Rick]

If Waterloo was the Master Exchange on the Southern Region they could have opened the window and listened out for Big Ben .

Explains why the Southern always ran 3 seconds late.

 

[edwin_m]

Explains why the Southern always ran 3 seconds late.

I thought it was 11 minutes (badger ate a junction box).

 

[The exile]

I do not know, but unless there was some local non-railway source, I presume that it was one of two methods. Either each exchange rang somewhere like Paddington, which had got their time from a reliable source, and then they (the exchange) carefully corrected their master clock in the exchange. Or from the first exchange each exchange rang the next down the line. (Or they jumped a few: Paddington told Swindon, which told several including Westbury and Bristol, with the last telling Taunton, etc.; meanwhile Paddington told Exeter, which told Newton Abbot, etc.)

It wouldn’t have been difficult: “Morning, Joe, Swindon here for the time check. It is coming up to 8.47.…it is 8.47…now.)

For a long time in most of the country, the railway would have been the source of accurate time - it also being the only reason most of the population would have needed the exact time. Not for nothing was GMT known for a period as “railway time”. There’s a description of the end of the process in Adrian Vaughan’s “Signalman’s Morning”, ISTR.

 

[John Webb]

.......Being pendulum clocks, the master pulse clocks were only adjusted by someone who knew what they were doing. However, they were extremely reliable. As I recall, they didn't need winding, they were powered electrically.

They are powered electrically, the pendulum being kept swinging by a magnetic impulse during part of the swing. The pendulum operates a 60 tooth wheel which at 30 second intervals triggers a pulse to the electrical clock mechanisms in the required circuit - the mechanisms were connected in series and the circuit voltage set depending on the number of mechanisms. The Master clock readout was one of those mechanisms so any fault with the circuit was (hopefully) quickly spotted! A switch on the master clock allowed the pulses to be turned off to retard the clocks or extra pulses to be applied to advance the clocks.

 

[Taunton]

... each exchange rang the next down the line. (Or they jumped a few: Paddington told Swindon, which told several including Westbury and Bristol, with the last telling Taunton ...

No wonder I was late for school ...

 

[Fleetwood Boy]

Looks like even modern systems are not immune to the challenges of the hour changing - unless there's some sort of wormhole between Carstairs and Carlisle. Screenshot is for the up Lowland Sleeper on Sunday night.

 

[Hellzapoppin]

I had a chat with one of my ex colleagues who used to adjust the clocks at Temple Meads in the 80s. There were 3 systems at the station apparently and when I asked where they got the accurate time from to do the adjustments he said "we used our watches, nothing more than that"
I remember buying a master pendulum clock and someone pinched it before I could take it home.

 

[edwin_m]

I looked at the BBC weather website between 0400 and 0500 on Sunday morning (which is still Saturday according to them, as it switches to the next day at 0600). It was showing an error for Saturday.

 

[Sultan1056]

Could they have got it from the GPO speaking clock? At least from 1936 anyway.

The internal railway telephone network had access to the speaking clock by dialling the number 016.

 

[zwk500]

A few years back when still living in Milton Keynes it took MK Central a good couple of weeks to update the clock after one change. No idea what the issue was with that one, but from memory it was only the biggest clock on the departure board that was affected, all other clocks on the platform screens etc I think did update.

 

[Falcon1200]

I have been in one of the UK's biggest hospitals on Sunday, yesterday and today and some of the clocks have still not been adjusted!

 

[edwin_m]

I was on an 810 today where the information screens were showing times for the train an hour later. Does that count?

 

[Pigeon]

For a long time in most of the country, the railway would have been the source of accurate time - it also being the only reason most of the population would have needed the exact time. Not for nothing was GMT known for a period as "railway time". There's a description of the end of the process in Adrian Vaughan's "Signalman's Morning", ISTR.

There is.

Later in the series he talks about doing night shifts around Oxford and the quiet of the night being suddenly broken by the synchronised cacophony as all the clocks in Oxford strike at once... apart from one in something called "the Tom Tower" which is always late, having defiantly stuck to local time when railway time became the standard for everything else. (So now I know what Terry Pratchett is going on about with the clocks striking in Ankh-Morpork.)

I think the distribution was on a tree system. So the various "Control"s would all get their time from Paddington at 10am, and then they would pass it on to the signalboxes over the bus line at 11am, or something along those lines.

 

[Dr Hoo]

In some areas it was possible to ‘loop together’ the various omnibus circuits, commonly done by the ‘booking boy’ at major junctions or signal boxes. This would enable a time check message to be sent to numerous locations effectively simultaneously, typically at (say) 9:00a.m.. Obviously the protocol was not to use the omnibus circuit (other than in an emergency) around time check time.

 

[Mcr Warrior]

Wasn't there once a little old lady by the name of Ruth Belville who "sold the time"? Apparently, she used to schlep up to the Royal Observatory in Greenwich to set her portable timepiece to Greenwich Mean Time, before then making her way around various locations in Central London (which may possibly have included a number of local railway stations) in order to then synchronise the time on her pocket watch with subscribers' clocks.

 

[Siemens Trains]

Explains why the Southern always ran 3 seconds late.

Slightly off topic but there's a clock at Waverley station in Edinburgh that seems to show the time 3 minutes ahead whenever I'm there. It's the analogue clock above the concourse between platforms 2 and 5.
I wonder if staff synchronise it with the inaccurate clock above the nearby North British Hotel.

While the hotel clock is rather famous for being wrong, an inaccurate station clock seems slightly unprofessional.

 

[edwin_m]

Slightly off topic but there's a clock at Waverley station in Edinburgh that seems to show the time 3 minutes ahead whenever I'm there. It's the analogue clock above the concourse between platforms 2 and 5.
I wonder if staff synchronise it with the inaccurate clock above the nearby North British Hotel.

While the hotel clock is rather famous for being wrong, an inaccurate station clock seems slightly unprofessional.

Perhaps that's the answer to the argument that flares up every few months on here about whether barriers and train doors should be shut before advertised departure time.

 

[Rescars]

Wasn't there once a little old lady by the name of Ruth Belville who "sold the time"? Apparently, she used to schlep up to the Royal Observatory in Greenwich to set her portable timepiece to Greenwich Mean Time, before then making her way around various locations in Central London (which may possibly have included a number of local railway stations) in order to then synchronise the time on her pocket watch with subscribers' clocks.

Seems she was carrying on her father's business which he had started in 1836, finally retiring in 1940. Concurrently (following on from #32), it seems that the Irish Mail carried a watch set GMT by the Greenwich Observatory to Ireland every day from 1848 until 1939. This accurate timepiece was taken by Royal Observatory staff to Euston where it was placed in the care of the guard and was used to regulate the clocks at stopping points en route to Holyhead. Here the watch was handed on to the steamer and so conveyed to Dublin. What happened when the clocks changed is anyone's guess. Two watches perhaps. That would only be relevant if the Irish Mail ran on Saturday nights of course. Those with access to Bradshaws will be able to find out more.

 

[WesternLancer]

There is.

Later in the series he talks about doing night shifts around Oxford and the quiet of the night being suddenly broken by the synchronised cacophony as all the clocks in Oxford strike at once... apart from one in something called "the Tom Tower" which is always late, having defiantly stuck to local time when railway time became the standard for everything else. (So now I know what Terry Pratchett is going on about with the clocks striking in Ankh-Morpork.)

I think the distribution was on a tree system. So the various "Control"s would all get their time from Paddington at 10am, and then they would pass it on to the signalboxes over the bus line at 11am, or something along those lines.

Tom Tower is the tower with clock at Christ Church college Oxford.

Tom is the name of the bell in the tower.

 

[Cricketer8for9]

Seems she was carrying on her father's business which he had started in 1836, finally retiring in 1940. Concurrently (following on from #32), it seems that the Irish Mail carried a watch set GMT by the Greenwich Observatory to Ireland every day from 1848 until 1939. This accurate timepiece was taken by Royal Observatory staff to Euston where it was placed in the care of the guard and was used to regulate the clocks at stopping points en route to Holyhead. Here the watch was handed on to the steamer and so conveyed to Dublin. What happened when the clocks changed is anyone's guess. Two watches perhaps. That would only be relevant if the Irish Mail ran on Saturday nights of course. Those with access to Bradshaws will be able to find out more.

And only relevant when the clocks changed, which practice began in WW1.

 

[edwin_m]

What happened when the clocks changed is anyone's guess. Two watches perhaps. That would only be relevant if the Irish Mail ran on Saturday nights of course. Those with access to Bradshaws will be able to find out more.

I'd expect that the watch was just left on the previous day's time and the people along the way knew they had to set their clocks an hour ahead or behind it. Or perhaps they set the watch to the next day's time before it left Greenwich. They wouldn't adjust it en route, as that would lose the accurate time.

 

[The exile]

And only relevant when the clocks changed, which practice began in WW1.

And not really an issue, since unless a clock has stopped, a regular and frequent time check is unlikely to require checking the hour as well (might as well ditch the clock if it does). The day con which the clocks changed would be known by anyone involved in such a check.