Understanding RealTimeTrains data

[Oncenor]

When tracking a service, I noticed they use a separate identifier in the URL: E.g. G59573 in https://www.realtimetrains.co.uk/service/gb-nr:G59573/2023-08-11/detailed . Why isn't the service's head code 1V57 used instead? I don't understand why they made a new identifier when one exists.

 

[pokemonsuper9]

When tracking a service, I noticed they use a separate identifier in the URL: E.g. G59573 in https://www.realtimetrains.co.uk/service/gb-nr:G59573/2023-08-11/detailed . Why isn't the service's head code 1V57 used instead? I don't understand why they made a new identifier when one exists.

Headcodes aren't unique per day like the UIDs are, try searching some headcodes the Elizabeth Line uses and you'll see that they reuse them.

 

[Oncenor]

Headcodes aren't unique per day like the UIDs are, try searching some headcodes the Elizabeth Line uses and you'll see that they reuse them.

Neither is the ID they use though? https://www.realtimetrains.co.uk/service/gb-nr:P71703/2023-08-10/detailed https://www.realtimetrains.co.uk/service/gb-nr:P71703/2023-08-11/detailed

 

[JonathanH]

Neither is the ID they use though? https://www.realtimetrains.co.uk/service/gb-nr:P71703/2023-08-10/detailed https://www.realtimetrains.co.uk/service/gb-nr:P71703/2023-08-11/detailed

That is the same train on successive days.

 

[SargeNpton]

The Unique Identity (UID) is allocated when trains are uploaded to Network Rail's Train Planning System.

It may only apply to a train on one day or it could be allocated to the same train for a complete timetable period. However, it is the only code that is unique on any one day. All other methods of identifying a train may be repeated on the same day in different parts of the country, or may be repeated on the same route at different times during the day where there may be an intensive service.

 

[Oncenor]

The Unique Identity (UID) is allocated when trains are uploaded to Network Rail's Train Planning System...

That is the same train on successive days.

Yeah I still don't get why the additional ID was necessary though. Both still have the same unique ID for a given day

 

[ainsworth74]

Yeah I still don't get why the additional ID was necessary

1V57 happens to be unique on the network today in that there aren't any other trains using that reporting number.

However take 2D06. Do you mean the 0430 Gravesend to Charing Cross? The 0628 Darlington to Saltburn? 0739 Leamington Spa to Stratford-upon-Avon? Or perhaps the 1845 London Liverpool Street to Cheshunt?

The UIDs are unique day by day so if you are looking at P55657 you know that that is the 0628 Darlington to Saltburn. There is no other train on the network today with that UID. This is important for planning and various other reasons. The reporting number is sufficient for signalling purposes as none of them are likely to show up to the same signaller at the same time. But the UIDs are important to ensure that you're dealing with the right service for other purposes.

Also, to be clear, this is nothing to do with RTT. These are internal industry identifiers that RTT is displaying.

 

[Oncenor]

1V57 happens to be unique on the network today in that there aren't any other trains using that reporting number...

Ahhh I see!!!

 

[SargeNpton]

Yeah I still don't get why the additional ID was necessary though. Both still have the same unique ID for a given day

Because it is the principal index in the current Train Planning System (and in the previous systems dating back 40 years or more).

 

[swt_passenger]

Ahhh I see!!!

There was a thread way back where the questioner asked about duplicated train IDs (aka headcodes). Then as now, 2P12 was given as a good example.

Duplicated Headcodes

While looking at http://traintimes.im I found the 0630SX Broadstairs/0658SO Faversham to St Pancras arr 0806 and the 0825 St P to Sheffield are both 1F13. Interesting that they're active in St P at the same time fortunately the responsibility of different Signalling Centres, but still a...

www.railforums.co.uk

So this is what RTT shows today, you'll quickly see it includes the Stourbridge shuttle which repeats 3 times:

Realtime Trains | Headcode Search

Realtime Trains is an independent source of live realtime running information for the Great British railway network.

www.realtimetrains.co.uk

 

[hwl]

Ahhh I see!!!

Headcodes are effectively only unique within an NR region and within a ~6 hour buffer window.

Southeastern are the worst culprit for using headcodes twice in one day (same route and stopping pattern but ~1/2 day apart).

 

[zwk500]

Headcodes are effectively only unique within an NR region and within a ~6 hour buffer window.

Southeastern are the worst culprit for using headcodes twice in one day (same route and stopping pattern but ~1/2 day apart).

There are several examples of headcodes in the same region within a 6 hour buffer - I'm fairly sure there's an avanti departure from Euston with the same headcode of rhe sleeper only a couple of hours ahead.

 

[jnjkerbin]

Another common example are the 2Hxx Charing X - Tunbridge Wells trains and the 2Hxx London Bridge - Beckenham Jn trains, which often cause erroneous reports between London Bridge and Bricklayers Arms where both can be scheduled within an hour or two of each other, albeit on different sets of lines.

 

[Boodiggy]

There are several examples of headcodes in the same region within a 6 hour buffer - I'm fairly sure there's an avanti departure from Euston with the same headcode of rhe sleeper only a couple of hours ahead.

1M11

 

[Horizon22]

Headcodes are effectively only unique within an NR region and within a ~6 hour buffer window.

Southeastern are the worst culprit for using headcodes twice in one day (same route and stopping pattern but ~1/2 day apart).

Used to be 6 hour, but I think the Elizabeth line has broken that now.

Often up to 4 trains a day with the same headcode, simply due to the sheer number of trains in sequence. Search any 9Wxx or 9Yxx headcode on a weekend and you’ll find a few.

 

[AMD]

Another example of reused headcodes - 2N99 at Northern - https://www.realtimetrains.co.uk/service/gb-nr:P45010/2023-08-11/detailed#allox_id=0 & https://www.realtimetrains.co.uk/service/gb-nr:P56393/2023-08-08/detailed#allox_id=0
Both however interact with Preston box, albeit the Blackburn train terminates at 1609 and the Blackpool train enters Preston control around 1800.

 

[Peter0124]

The ID changes on Saturdays and Sundays sometimes. Also the ID usually changes after new timetable change days.

 

[norbitonflyer]

Are they completely unique for a given day though? Does an overnight train arriving at its destination on Tuesday morning have a different UID to the service starting out on Tuesday evening?

 

[SteveHFC]

Are they completely unique for a given day though? Does an overnight train arriving at its destination on Tuesday morning have a different UID to the service starting out on Tuesday evening?

No - because the one arriving at its destination on Tuesday morning will have started on Monday evening.

 

[zwk500]

Are they completely unique for a given day though? Does an overnight train arriving at its destination on Tuesday morning have a different UID to the service starting out on Tuesday evening?

That would be the Monday train and Tuesday train. The fact it happens to run into Tuesday morning does not affect the UID rules. The departures are still 24 hours apart.

 

[D6975]

The Cumbrian Coast has lots of 2 a day headcodes, surprising as it's not that busy a route.

 

[geoffk]

Another example of reused headcodes - 2N99 at Northern - https://www.realtimetrains.co.uk/service/gb-nr:P45010/2023-08-11/detailed#allox_id=0 & https://www.realtimetrains.co.uk/service/gb-nr:P56393/2023-08-08/detailed#allox_id=0
Both however interact with Preston box, albeit the Blackburn train terminates at 1609 and the Blackpool train enters Preston control around 1800.

This must be very common with class 2 trains surely, but less so with class 1. What about freights?

 

[Tom]

Are they completely unique for a given day though? Does an overnight train arriving at its destination on Tuesday morning have a different UID to the service starting out on Tuesday evening?

The uniqueness is defined as the combination of service UID and departure date from planned origin.

e.g. if a train on Monday actually started short and departed en-route from its first station on a Tuesday, and the Tuesday version ran to plan, the altered Monday train is still unique as it was planned to depart on Monday

This must be very common with class 2 trains surely, but less so with class 1. What about freights?

Not entirely uncommon.

 

[endofthetunnel]

This must be very common with class 2 trains surely, but less so with class 1. What about freights?

Not uncommon for class 1 or freights to not be ‘unique’ on a day at all.

Most examples on this thread have been of the same headcode on the same panel, but it’s just as important for systems to differentiate between them across the country - for example a quick search on RTT shows there are 5 1A04s today, each of course needing their own UID.

 

[jfollows]

Going back in time, headcodes were sometimes used as route indicators, for example 2H54 was used for Alderley Edge-Altrincham via Stockport and 2H53 for Alderley Edge-Altrincham via Styal, in both directions. So two trains with the same headcode often passed each other. This from 1974, still the case in 1977, but at some point it was changed. It couldn't happen today for obvious reasons but also because Alderley Edge is now deemed to be in the Stoke-on-Trent division like Crewe and so trains terminating there are now 2Kxx rather than 2Hxx.

 

[_toommm_]

This must be very common with class 2 trains surely, but less so with class 1. What about freights?

Forgetting the xQxx and xZxx headcodes as they’re for special circumstances, there’s 2,400 unique headcodes for each class of train per day, 0 through 9. I’m sure in the 1Xxx and 2Xxx series, there’s probably ones unused, put also as noted above lots of duplicates.

 

[Vexed]

There's some very close ones at Farringdon between the Elizabeth line and Thameslink such as the first 9T43 departing at 1527 then Thameslink's 9T43 departing less than half an hour later at 1554.

Today there's also an early morning TL 9T43 which is 9W13 in the WTT but is a 9T today because it's running via London Bridge instead of Elephant & Castle/Streatham Common.

 

[Horizon22]

There's some very close ones at Farringdon between the Elizabeth line and Thameslink such as the first 9T43 departing at 1527 then Thameslink's 9T43 departing less than half an hour later at 1554.

Today there's also an early morning TL 9T43 which is 9W13 in the WTT but is a 9T today because it's running via London Bridge instead of Elephant & Castle/Streatham Common.

Although it’s the ‘same’ station, they are different infrastructure routes of course.

 

[Class15]

This must be very common with class 2 trains surely, but less so with class 1. What about freights?

“4M07” generally has both a Tilbury - Daventry and Felixstowe - Birch Coppice every weekday.

 

[Class15]

The uniqueness is defined as the combination of service UID and departure date from planned origin.

e.g. if a train on Monday actually started short and departed en-route from its first station on a Tuesday, and the Tuesday version ran to plan, the altered Monday train is still unique as it was planned to depart on Monday


Not entirely uncommon.

It’s a little confusing as the headcode system on the NLL means that there is generally one 2Nxx going one way per day and another 2Nxx going the other!