Telling the time

[43106]

This is going to sound really idiotic, but what time standard do the TOCs and/or NR use for train departures? Similarly, what standard do train staff use when they are at home?
The BBC used to have a clock on BBC1 and BBC2 which, to all intents and purposes, was spot on. I believe that these clocks were directly linked to the time signals transmitted from Rugby or Droitwich. Therefore, train-staff could set their wristwatches to time with a great degree of accuracy.
The 'mechanical' clocks hanging from (say) station platform canopies are probably derived from a similar source, but, as the numerics are in the form of '7-segment' displays, they are generally knackered, with at least 1 segment being jammed. (I'm particularly thinking of Kings Cross, especially one on Platform eight)
However, Digital TV and Radio no longer do time signals of any description. The reason for this is the time delay between the digital signal being transmitted and being received by us punters. This time delay can vary a bit, by up to a couple of seconds from receiver to receiver.
So, what do we do? What do the train companies do?

 

[EM2]

Well, at St Pancras, the main station clock gets a signal from Anthorn:
http://en.wikipedia.org/wiki/Time_from_NPL
The 'subsidiary' clocks get their signal from the main clock.

 

[Mojo]

And of course clocks on stations can differ - anyone ever stood and noticed at New Street that the clock above the ticket barriers is faster than the one on the departure boards

 

[O L Leigh]

I have a railway watch that picks up the time signal from Rugby, or so I assume. When the station clocks are running right these show exactly the same time as my watch to the second, so I guess they are synchronised to the same source.

O L Leigh

 

[1D53]

I have a railway watch that picks up the time signal from Rugby, or so I assume. When the station clocks are running right these show exactly the same time as my watch to the second, so I guess they are synchronised to the same source.

O L Leigh

Fair few TOC's have them issued, including Northern.

 

[Philip Elliott]

I have a railway watch that picks up the time signal from Rugby, or so I assume. When the station clocks are running right these show exactly the same time as my watch to the second, so I guess they are synchronised to the same source.

O L Leigh

Rugby was switched of years ago now Most of the masts went with indecent haste

 

[O L Leigh]

Fair enough. But the signal is still coming from somewhere.

Besides, all those masts were not just for the time signal. Like the similar site near Daventry, these had many other purposes including radio communication.

O L Leigh

 

[DaveNewcastle]

However, Digital TV and Radio no longer do time signals of any description. The reason for this is the time delay between the digital signal being transmitted and being received by us punters. This time delay can vary a bit, by up to a couple of seconds from receiver to receiver.
So, what do we do? What do the train companies do?

Not entirely correct!
The "6 pips" on the hour on many BBC and other radio stations are accurate, but ONLY IF YOU LISTEN TO THE ANALOGUE TRANSMISSION.
The beginning of the sixth pip indicates the hour exactly, and does come from the National Physical Laboratory - the 1kHz (kilohertz) tone comes from the local radio station but the on/off switching of that tone comes down a direct wire to the studio from London.
Sure, the DAB, Digi-TV, internet radio and satellite versions suffer from encoding delays at the transmitter plus decoding delays in your receiver, which can add up to several seconds (worst case is 7 secs I beleive), but you can rely on the instantaneous transmission over analogue radio and set your clock to that sixth pip with confidence.

 

[43106]

Fair enough. But the signal is still coming from somewhere.

I'd no idea Rugby had closed down. I actually made use of Rugby in 1976 when I used the time signal (100MHz) to calibrate the clock frequencies of various digital counters. They had an accuracy of 100.00MHz +/- 0.01Hz, or +/-0.00000001% !
Anyway, if Rugby is off-air, it's probably Droitwich, in Worcestershire, that puts out a time signal. I suspect that the originating signal comes from The National Physics Laboratory at Teddington in South-West London.
If TOCs (or some of them) issue radio-watches, what are the travelling public supposed to use?

 

[DaveNewcastle]

Fair enough. But the signal is still coming from somewhere.

They moved in, I think, 2006 to Anthorn in Cumbria
But (I could be wrong here) the BBC's AM Long wave transmissions for the southern half of the UK still comes from Davetry. And that includes our pips!

 

[43106]

Not entirely correct!
The "6 pips" on the hour on many BBC and other radio stations are accurate, but ONLY IF YOU LISTEN TO THE ANALOGUE TRANSMISSION.
The beginning of the sixth pip indicates the hour exactly, and does come from the National Physical Laboratory - the 1kHz (kilohertz) tone comes from the local radio station but the on/off switching of that tone comes down a direct wire to the studio from London.
Sure, the DAB, Digi-TV, internet radio and satellite versions suffer from encoding delays at the transmitter plus decoding delays in your receiver, which can add up to several seconds (worst case is 7 secs I beleive), but you can rely on the instantaneous transmission over analogue radio and set your clock to that sixth pip with confidence.

This is all true, BUT analogue is going to be phased out. The analogue TV has already gone in Whitehaven (and probably elsewhere). In anticipation of the entire BBC TV output going digital, they have discontinued showing clocks on any of its channels, because of the encoding and decoding delays (I HAD heard it was as much as 7 seconds delay, but I didn't believe it!). With the advent of DAB radio, the time pips will also go, as analogue radio will also be phased out.
So, where does that leave us?
--- old post above --- --- new post below ---

They moved in, I think, 2006 to Anthorn in Cumbria

Where's Anthorn? The only large-scale transmitting facility that I'm aware of in Cumbria is at Silloth, on the north-west coast, west of Carlisle. This is (or was) an ELF transmitting/receiving station for submarines.

But (I could be wrong here) the BBC's AM Long wave transmissions for the southern half of the UK still comes from Daventry. And that includes our pips!

I'm moderately sure that Daventry puts out BBC Long Wave for the entire UK. I regularly listen to it for the live cricket, and it's not a particularly good signal!

 

[DaveNewcastle]

So many questions!

This is all true, BUT analogue is going to be phased out. . . .
With the advent of DAB radio, the time pips will also go, as analogue radio will also be phased out.
So, where does that leave us?

Two responses: long wave & short wave AM radio may NOT be withdrawn - I don't know, but they serve purposes which domestic broadcasting don't reach.
But that's not the whole story - there are moves to deal with the latency delays in digital transmission and reception. Just one is the simple expedient of using the instantaneous wired time signal from the NPL to switch a local sound source (which is what happens at present - see my prev posts) but within the consumer's equipment.

Where's Anthorn? The only large-scale transmitting facility that I'm aware of in Cumbria is at Silloth, on the north-west coast, west of Carlisle. This is (or was) an ELF transmitting/receiving station for submarines.

a little to the due west of Carlisle. I understand that its the home of the NPL time clock. (In response to O L Leigh's question) Its NOT the radio transmitter! The time signal passes by wire to London, as it used to do from Warwickshire.

I'm moderately sure that Daventry puts out BBC Long Wave for the entire UK. I regularly listen to it for the live cricket, and it's not a particularly good signal!

No, its not the only one That's why they have a duplicate transmitter in Scotland, and for the poor folks who live half way between the two (incl Newcastle & Carlisle!) where the main transmitters are both weak and interfere with each other, they installed local "Medium Wave" repeaters.
But the automated equipment we use takes its time signal from a sub-sonic code of date and time which is transmitted on LW simultaneously with the audio programme (and any "pips" it might transmit).

I think there's confusion here between the location of The One official source of UK time signals and the radio transmission system to consumers.
The Time (capital letters) comes the NTL in Cumbria.
The tone we hear comes from our local radio studio.
The switching of that tone is in the studio but controlled from the NTL.
The automated clocks we have will continue to work correctly - they sync to the inaudible tones transmitted as digital signals on the long-wave radio transmission from Warwicks and Central Scotland.
There ARE flaws in the system, which I have had to deal with, when there are very confused times (eg, 2 mins past 2 am on 2nd of Feb 2002) but the encoding technology could not be upgraded without significant equipment replacements.

 

[Sir_Clagalot]

I use a £15 timex watch that I check against a wall clock that checks itself with the time signal. It's usually within 10-15 seconds of the correct time, and stays that way! Even my old timex (8years old) is still going, though is has lost a couple of minutes since I stopped wearing it on account that the battery could go when at work!

 

[Geezertronic]

I just sync my PC to an external time source and when I sync my phone with my PC it does the time as well (if required). I don't wear watches, phone does the job for me

 

[Sir_Clagalot]

All very well but we're not supposed to use our phones when dispatching a train!!!
Also, the time display on phones does tend to be just hours and minutes, where as Traincrew need seconds too

 

[Geezertronic]

All very well but we're not supposed to use our phones when dispatching a train!!!

I wasn't actually aware of that... in that case wouldn't it be better to go by whatever the station/platform clock says since that is the one the passengers will also go by? It should then be the responsibility of the station managers to ensure the clocks are kept to time?

Or is that too much of a simplistic view from an outsider looking in?

 

[Mojo]

Or is that too much of a simplistic view from an outsider looking in?

Some stations don't have clocks, in which case I'd imagine a well-timed watch would be essential for traincrew to avoid leaving early or late.

 

[Sir_Clagalot]

Even if there is a station clock, it is not always correct or working!!! Hence the use of a well-timed watch is essential!! Also knowing what time you are meant to be departing is helpful !!

 

[Geezertronic]

See I thought I was being a simpleton

 

[merlodlliw]

Some stations don't have clocks, in which case I'd imagine a well-timed watch would be essential for traincrew to avoid leaving early or late.

Good morning,

All this reminds me of the time when a clock was sent from Euston to Holyhead daily over a hundred years ago, so the train left Holyhead on London time.

Anyhow I have a radio controled clock bought at Aldi last year, this gets
its time from Germany on LW, however this morning at 0700 the pips on radio 4 FM on my sony portable were exact to the second with the Aldi bought clock.

I fully agree on Digital the delay is seconds out. And Wrexham General station has no clock, yet the displays inform of delays without showing any real time.

Also as Wrexham Gen is now a Terminus for W/S,VT & some ATW rail buses
no one as any idea of how these trains are running, if at all as only departures are shown, I have seen the local taxi firm on the dog & bone to
Gobowen & Chester taxis to try find out.

 

[HSTfan!!!]

If you were to set your watch in bristol temple meads, and then catch a train to Newport, there is a time warp of 10 seconds lol
I don't actually carry a watch on duty, I don't know why really, but we all tend to go by the station clock.