Train planning rules question

[pompeyfan]

As many will know, there is a general rule that the letter contained within a headcode or train reporting number will indicate the route the train is taking. For trains travelling between grouping regions (Western, Southern, Anglia etc) the letter will usually indicate the destination region.

From memory

xExx - North East
xLxx - London & Anglia
xMxx - Midlands / North West
xOxx - Southern region
xSxx - Scotland
xVxx- Wales & Western

A lot of modern day train services run to this principle, if you look at Cross Country etc or the majority of freight.

However in true railway style there are also several exceptions

GWRs 1Fxx Cardiff - Portsmouth
SWRs 1Lxx Waterloo - Exeter St Davids
GWR & SWR services to Reading from Basingstoke running as 1Jxx / 2Jxx.

I’m sure there are countless others.

Looking at old photographs and captions, this hasn’t always been the case, with both the first two service groups running to their previous 1O/1V running numbers.

Yet conversely there are also service groups that retain 2/3 trains per hour across regions that have kept their regional headcodes (as mentioned above Cross Country, but also the North Downs services)

My question is why have some inter regional services transitioned to a booked routing letter, whilst others have retained their pattern of regional headcodes.

 

[JonathanH]

GWRs 1Fxx Cardiff - Portsmouth

Isn't this just an aid to the user of the reporting codes. If CrossCountry run 1Oxx trains from Manchester to Bournemouth through Southampton and 1Vxx trains from the North through Bristol, then having completely different 1Oxx and 1Vxx trains on crossing routes isn't going to be ideal.

The CrossCountry services are in the lower range of 1Oxx numbers, while North Downs are in the higher range of those numbers. While both are at Reading it would be fairly difficult to confuse them.

 

[pompeyfan]

Which leads to the question of why did only some change? There are a handful of high numbered XC services from memory.

I do get your point though, especially with Reading where they wouldn’t generally interact.

 

[WAB]

Not my area of expertise but I assume that the reporting number principles were strongly adhered to in the past, and any deviation has been locally arranged when operations management have requested it and the train planners have been willing to make the change, hence the inconsistency.

With increased computerisation and far fewer ad-hoc moves, I suppose reporting number letters by service group and destination, rather than legacy region is more useful in many cases.

 

[Tomnick]

I suspect that the reason is simply that the increased frequency on many routes mean that there are now far too many inter-regional services over some boundaries for it to be workable any more. Probably evolution rather than deviation, but it makes sense to take some routes or service groups away from that long-established convention. Just think how many 1Mxx services there'd be descending on Manchester otherwise!

The problem now is when planners start making their own rules up and these aren't challenged. A good example is Skegness services, which were taken away from the 2Exx/2Mxx convention some time ago (a narrow band of numbers was allocated to each route across the regional boundary) to 2Sxx and now also 2Oxx for services on the way back. Sensible, as there clearly is little likelihood of them conflicting with class 2 inter-regional services to Scotland or the former Southern region. The same was then applied to the summer Saturday additional services though, which run as 1Sxx/1Oxx, with potential for conflict and confusion at both Grantham and Derby. When Nottingham was blocked for the summer in 2013, those extras ran via Peterborough, and I'd be amazed if the 1Sxx weren't wrong-routed by Doncaster PSB at Grantham at least once!

 

[IrishDave]

In general they've tried to distinguish between service groups by using different number ranges, and I think it's probably only where they can't do that that they have moved to using different letters.

For example the 1Vxx range is divided up as follows in the NW&C Timetable Planning Rules:

• 00-20 Birmingham New Street to Gloucester/Cardiff via Chepstow
• 20-30 Birmingham New Street to Worcester stations /Malvern/Hereford/Gloucester
• 40-75 Birmingham New Street to Bristol/Plymouth/West Country
• 80-95 Birmingham New Street to Reading via Leamington Spa

If other trains are to use 1Vxx headcodes, they shouldn't use the same number in the same area, but the same number in a different area would be okay. So the Gatwick-Reading trains can also use the 1V34-1V67 range without overlapping at Reading. (I think the 1O8x/1O9x trains are trains that used to terminate at Reading but got extended through to Southampton, and therefore changed from 1V to 1O but seemingly kept their old number.)

But it means that a Portsmouth-Cardiff train couldn't use any of 00-20 (as it would clash at Cardiff) or 40-75 (as it would clash through Bristol), and that doesn't leave that many numbers to play with, so it's easier to give it its own letter and make them 1Fxx. Although the other direction could probably have stayed as 1Oxx, I can believe it would have made sense to disambiguate the Bristol-Waterloo trains (which definitely did run as 1Oxx) from the Cardiff-Portsmouth trains by making the latter 1Fxx as well (and using even/odd to distinguish between directions).

By contrast, the 1Mxx range is not divided up in the rules. (Indeed, if anyone can discern any logic to how the 1Mxx range is numbered, I would love to know!) But they have to cover all XC to Manchester, as well as every XC Cardiff to Nottingham and every Hereford/Worcester to Birmingham train. That pretty much fills up the 1Mxx range (without duplicating numbers) just for trains through Birmingham.

Therefore, 1Nxx headcodes get used for XC services from Stansted/Cambridge to Birmingham, while 1Rxx headcodes get used for EMR services from Norwich to Liverpool. Both of those services can use 1Lxx in the other direction because there's not as much pressure on the 1Lxx number range.

== Doublepost prevention - post automatically merged: 25 Oct 2024 ==

I suspect that the reason is simply that the increased frequency on many routes mean that there are now far too many inter-regional services over some boundaries for it to be workable any more. Probably evolution rather than deviation, but it makes sense to take some routes or service groups away from that long-established convention. Just think how many 1Mxx services there'd be descending on Manchester otherwise!

The problem now is when planners start making their own rules up and these aren't challenged. A good example is Skegness services, which were taken away from the 2Exx/2Mxx convention some time ago (a narrow band of numbers was allocated to each route across the regional boundary) to 2Sxx and now also 2Oxx for services on the way back. Sensible, as there clearly is little likelihood of them conflicting with class 2 inter-regional services to Scotland or the former Southern region. The same was then applied to the summer Saturday additional services though, which run as 1Sxx/1Oxx, with potential for conflict and confusion at both Grantham and Derby. When Nottingham was blocked for the summer in 2013, those extras ran via Peterborough, and I'd be amazed if the 1Sxx weren't wrong-routed by Doncaster PSB at Grantham at least once!

Specifically on the Skegness diverts via Peterborough in 2013, that year they were headcoded 1S01/1S02/1S03/1S04 - which would otherwise be first thing in the morning (as 1Sxx LNER trains do follow a sequence in order through the day). So hopefully them being "out of sequence" would have given Doncaster PSB enough time to pause for thought!

In any other year, I thought the 1Sxx/1Oxx diverts were headcoded as Class 1 specifically because they avoided Grantham (i.e. they ran via Allington West Jn-Allington North Jn)?

 

[Wilts Wanderer]

But it means that a Portsmouth-Cardiff train couldn't use any of 00-20 (as it would clash at Cardiff) or 40-75 (as it would clash through Bristol), and that doesn't leave that many numbers to play with, so it's easier to give it its own letter and make them 1Fxx. Although the other direction could probably have stayed as 1Oxx, I can believe it would have made sense to disambiguate the Bristol-Waterloo trains (which definitely did run as 1Oxx) from the Cardiff-Portsmouth trains by making the latter 1Fxx as well (and using even/odd to distinguish between directions).

Until they were withdrawn, GWR’s services to Brighton ran under ‘O‘ interregional headcodes as opposed to the ‘F’ route-based headcodes of the Portsmouth service in order to distinguish them at Cosham Jn and avoid a potentially extremely disruptive misrouting.

In the past 1Fxx was used for Paddington to Oxford - I’ve often wondered why these changed to 1Dxx as there isn’t another F grouping in the Thames Valley to my knowledge.

 

[Class 170101]

Some trains are now Class 9s due to running out of letters and avoiding clashes.

 

[pompeyfan]

Very interesting, cheers for the replies. I hadn’t considered the fact that there could be clashes up and down the country if a specific band of numbers weren’t used, which then limits the number of available headcodes up for grabs.

With a move over the last 30 years from length of train to frequency of service, I can see why there is now a lot of congestion in what would have been the 1M and 1V range specifically.

 

[IanXC]

However in true railway style there are also several exceptions

...
GWR & SWR services to Reading from Basingstoke running as 1Jxx / 2Jxx.

I’m sure there are countless others.

Western Region stoppers from Reading towards the Southern Region were 2Axx in the original scheme - so it isn't correct to say that cross boundary services always operated to the inter-regional scheme. Broadly as the scheme started if the train was operated by one district (traincrew and rolling stock), in this case the Western Region's London District, it would operated with that district's letter, in this case "A". For the most part these services would be class 2 given the size of districts at that time.