4 character headcodes - a note for the interested newcomer

[whole diary]

[grahame]

A post for members (and lurkers) who haven't got as deeply into this stuff as some of us poor souls, as they still have a life away from public transport 

3B63

A reference from yesterday - what does it mean?  Why use such a code system?

Answering the second question first - why use such a system?

The 06:12 from Swindon to Westbury (and perhaps to Southampton) is also the 06:36 from Melksham to Trowbridge. Same train, same driver, mostly the same passengers, and there's a need within the operational and planning of the railways to have a clear, unique way of identifying the train so that when people communicate, they know they're taking about the same service that's ... running late, overcrowded, conveying royalty, or whatever it is ... hence the codes.  Oh - the example I've used is 2M02 and it's also the 05:17 from Gloucester and the 06:05 (arrival) at Swindon and the 08:09 arrival into Southampton Central.

First question - what does it mean?

The digit on the beginning is the class of train ... not totally sure of all of these but
1 - Important passenger train - a main express service
2 - Less important passenger train (in the eyes of some?)
3 - Empty passenger train that has to be run to time as it's on its way to form a class 1 or class 2 service
5 - Empty passenger train for which timing isn't so critical
6 - Fast freight
9 - Monty Python train - something different. e.g. passenger train with wrong stock so it can't use certain platforms
0 - "light" locomotive
Anyone care to comment or fill in 4, 7 and 8 if they (still) exist

The letter following - the M in our 2M02 - used to be a destination area, but I believe that these letters have been somewhat muddied;  they still tend to group services into sets - so most of what I see on the TransWilts are "M"s.  In BR^▸ (British Rail(ways)) history, there were certain interregional codes - V for Western, O for Southern, for example - and we still have "Train Two Thousand" as I call it - 2O00

The final two digit are a sequence number for the train on the route - very often odd numbers in one direction, and even numbers in t'other.  Not an absolute rule though - 2M03 followed by 2M04 and evens to 2M18 northbound, 2M02 and 2M05 and odds to 2M15, then 2O00 and 2M17 southbound.  As trains run in opposite directions with interleaved numbers, there are some stations where trains don't call in numeric sequence.  For example, 2M18 calls at Melksham before 2M17.

I note that there's nothing in our area called 2M19 or 2M20, and I commend these numbers (and trains running logically where such numbers would run) to GWR^▸ (Great Western Railway) and to the DfT^» (Department for Transport - about) as they plan for the extra year, the next two years of probable direct award, and the following 7 to 10 year franchise.



Edit to correct title

[martyjon]

Refer to :-    https://en.wikipedia.org/wiki/Train_reporting_number

[eXPassenger]

Sorry to be pedantic but the heading should be '4 character headcodes' as the second character is not a digit.

[grahame]

Sorry to be pedantic but the heading should be '4 character headcodes' as the second character is not a digit.

Indeed - I have edited original post and this reply, so any further responses should pick up the change

[SandTEngineer]

To be honest the 'Modern Day Railway' has made a complete mess of this.  It was a very good system when it started
http://www.2d53.co.uk/Headcode/headcode.htm and http://myweb.tiscali.co.uk/gansg/3-sigs/bellhead.htm

...but this is much more interesting....http://www.warwickshirerailways.com/misc/headcodes.htm  In particular I like the section on multi-part summer trains with up to 5 seperate portions.  IET^▸ (Intercity Express Train) 25 car trains anybody.....

....before I get told off for thread drift, back to the current days.  Here is the NR^» (Network Rail - home page) list of current train classifications:

1     
Express passenger train, nominated postal or parcels train, breakdown or overhead line equipment train going to clear the line or returning from there (Code 1Z99), traction unit going to assist a failed train (1Z99), or a snowplough going to clear the line (1Z99).

2    
Ordinary passenger train, breakdown or overhead line equipment train not going to clear the line (2Z99), or an Officers’ special train (2Z01).

3   
Freight train which can run at more than 75 mph, parcels train, or empty coaching stock train if specially authorised.

4   
Freight train limited to 75mph.

5   
Empty coaching stock train.

6   
Freight train limited to 60mph.

7   
Freight train limited to 45mph.

8   
Freight train limited to, or timed to run at, 35mph or less.

9    
Eurostar train and certain long distance Cross Country services are allocated 9xxx headcodes to help signallers identify a long-distance inter-regional express passenger service from a regional Class 1 express service.

0   
Light locomotives.

[rogerw]

Euston to Scotland via Birmingham service are also class 9 to identify the routeing

[TonyK]

Euston to Scotland via Birmingham service are also class 9 to identify the routeing

As do Virgin services from Euston to/via BHM.

[paul7575]

Class 9 is also used by LO ELL services and some Thameslink through trains from GN to SN networks.  Also sometimes used as a temporary flag to show routing limitations, like when some classes were barred from certain platforms at Salisbury recently.  As mentioned above.

I think it’s fair to say that Class 9 is now getting used far more often than a few years back.

Paul

[martyjon]

Many years ago the use of X and Z as the second character denoted a special excursion or what today is a STP service, X being an internal regional service and Z being an inter-regional service or was it the other way round.

Having said that, 1X01 isn't used very often nowadays.

[Western Pathfinder]

However The Royal Train was out and about on the S&C^▸ (Settle and Carlisle ) earlier this week.

[Worcester_Passenger]

A post for members (and lurkers) who haven't got as deeply into this stuff as some of us poor souls, as they still have a life away from public transport 
...
The final two digit are a sequence number for the train on the route - very often odd numbers in one direction, and even numbers in t'other.  Not an absolute rule though - 2M03 followed by 2M04 and evens to 2M18 northbound, 2M02 and 2M05 and odds to 2M15, then 2O00 and 2M17 southbound.  As trains run in opposite directions with interleaved numbers, there are some stations where trains don't call in numeric sequence.  For example, 2M18 calls at Melksham before 2M17.

A possibly-stupid question - why is the odd/even split so erratic? On RTT^» (Real Time Trains - website) for the Cotswold line, I see these numbers. Towards London we have trains 1Pxx, where xx is 04, 07, 12, 14, 18, 22, 23, 25, 27, 29, 31, 33, 36, 37, 39, 42, 45, 47, 49, 51. So mostly odd, but sometimes even in the peaks.

Away from London, the trains are 1Wxx, where xx is 11, 12, 14, 16, 00, 19, 01, 23, 25, 27, 29, 31, 32, 33, 02, 36, 03, 04, 39, 42. Again mostly odd. The low numbers 00-04 are the trains that go through to Hereford.

What's the logic of all of this? Are there two planners involved, who are not on speaking terms?

   

[stuving]

A possibly-stupid question - why is the odd/even split so erratic? On RTT^» (Real Time Trains - website) for the Cotswold line, I see these numbers. Towards London we have trains 1Pxx, where xx is 04, 07, 12, 14, 18, 22, 23, 25, 27, 29, 31, 33, 36, 37, 39, 42, 45, 47, 49, 51. So mostly odd, but sometimes even in the peaks.

Away from London, the trains are 1Wxx, where xx is 11, 12, 14, 16, 00, 19, 01, 23, 25, 27, 29, 31, 32, 33, 02, 36, 03, 04, 39, 42. Again mostly odd. The low numbers 00-04 are the trains that go through to Hereford.

What's the logic of all of this? Are there two planners involved, who are not on speaking terms?

This is a guess - based on observation, which is no substitute for knowledge!

If there is a "normal" method, it uses the same letter with odds up and evens down. The numbers are best spread over the range leaving some unused, rather than consecutive at the low end, as it makes it easier to add or remove one train without renumbering the lot.

That's fine until you get close to 50 services each way, then you have to think again. A number of options are available (there are probably others too):

• Use different letters for up and down.
• Split the day between letters based on time.
• Divide the service between different routes or stopping patterns.

The question now becomes why pick one of those rather than another?

[Adelante_CCT]

1Pxx also involves the Oxford to Paddingtons, so therefore they are generally in order, east of Oxford anyway. 23,25,27,29 etc being hourly, 24,26,28 etc being the other half hour, but starting from Oxford

[plymothian]

Many years ago the use of X and Z as the second character denoted a special excursion or what today is a STP service, X being an internal regional service and Z being an inter-regional service or was it the other way round.

Having said that, 1X01 isn't used very often nowadays.

Z is still used for a [sometimes very] STP working, not matter the distance.  The Royal train was 1Z70 this week.

[Worcester_Passenger]

1Pxx also involves the Oxford to Paddingtons, so therefore they are generally in order, east of Oxford anyway. 23,25,27,29 etc being hourly, 24,26,28 etc being the other half hour, but starting from Oxford

Thank you for that - I never look at things that only run east of Oxford. A blinkered view I know, but hopefully understandable!