Wheelbase of bogie CCT vans

[mortsy]

I will be ordering some custom transfers but have query on wheelbase measurement of NER/LNER bogie CCT stock.

Is the wheelbase, as displayed on the van sides the distance from:-

1. outer axle to outer axle
2. bogie pivot centre to bogie pivot centre
3. inner axle to inner axle

Many thanks

Mortsy

[markw]

I don't think it was applied to bogie stock, only 4 and 6 wheeled stock.

[Fat Controller]

Looking at Paul Bartlett's site, the inscription on a bogie, ex-LNER, van gives:-

Length Inside

Width over body

Extreme Width

Extreme Height

Distributed Weight.

There is no mention of wheelbase or bogie-centres.  Photos of 4-wheel vehicles give the wheel-base, however.

[mortsy]

Thanks to respondents - most helpful

[Compound2632]

I think it's the case that the wheelbase was displayed on 4-wheeled vehicles because it affected what class of trains they could be run in. As there was no such restriction for bogie vehicles, it was not necessary to display it.

[Wickham Green too]

I'm not sure it's that simple ....... looking through Vol 3 of Historic Carriage Drawings, you can find 'XP' marked vehicles with wheelbase of between 10'0'' and 23'6'' - which would be allowed to run in exactly the same types of train !  Certainly anything below 10' would not be 'XP' rated - but why was an exact measurement required for those which were ?

[Sitham Yard]

20 hours ago, Wickham Green too said:

I'm not sure it's that simple ....... looking through Vol 3 of Historic Carriage Drawings, you can find 'XP' marked vehicles with wheelbase of between 10'0'' and 23'6'' - which would be allowed to run in exactly the same types of train !  Certainly anything below 10' would not be 'XP' rated - but why was an exact measurement required for those which were ?

Restrictions applied if under a certain length. BR General Appendix dated 1960 states vehicles with wheelbase less than 15 feet must not exceed 60 mph. Marking vehicles with the exact wheelbase gives scope for varying this restriction which may have happened over the years.

Andrew    

[Wickham Green too]

I suspect the 1960 Appendix requirement might, indeed, have superseded 'XP' branding ...... but exact wheelbases were indicated long before that.

[keefer]

The exact nature of any restrictions at the current time were usually listed in the Working Timetables - certainly in BR times throughout the 1960s and into the '70s, the exact requirements changed with, generally speaking, more restriction/lower speed imposed on those wagons with shorter wheelbases as the years went on.

Probably also linked to the overall speed increase of ordinary passenger trains.

Eventually, as mentioned above, the 'XP' or equivalent rating was only for those with WB over 15' and roller bearings.

I don't have a WTT handy but the 'spade' and 'double spade' symbols were used to indicate various restrictions on stock.

Even then some trains were marked 'N.F.W.' - No 4-whl vehicles permitted.

[Sitham Yard]

3 hours ago, Wickham Green too said:

I suspect the 1960 Appendix requirement might, indeed, have superseded 'XP' branding ...... but exact wheelbases were indicated long before that.

No the 1960 General Appendix sets out the requirements for 'non-passenger carrying Coaching Stock or Braked Freight Stock' to run in passenger trains and specifically states 'Four-wheeled vehicles conforming to the above requirements and having a wheelbase of 10ft or over are marked "X.P." together with the wheelbase.'

 

I believe that at that time only a relatively small number of trains exceeded 60 mph and this was marked in the Working Timetables as mentioned above.   

 

I have no knowledge of what happened later.

Andrew      

[Sitham Yard]

3 hours ago, Wickham Green too said:

I suspect the 1960 Appendix requirement might, indeed, have superseded 'XP' branding ...... but exact wheelbases were indicated long before that.

It is perhaps worth pointing out that the 1960 General Appendix was the first General Appendix issued by BR. Before that I think that the GA's issued by the big four remained in force with amendments or supplements being issued by BR. The XP markings appear to have only started in the late 1930's although restrictions on vehicles to run in passenger trains would have been in force before that.

Andrew 

[Wickham Green too]

10 hours ago, Sitham Yard said:

No the 1960 General Appendix .... specifically states 'Four-wheeled vehicles conforming to the above requirements and having a wheelbase of 10ft or over are marked "X.P." together with the wheelbase.' ....

Ah, yes - found it now .................. it still doesn't explain why the precise wheelbase needed to be marked when they could simply have used 'XP' for 10' to 14'11'' stock and, say, 'XXP' ( or something completely different ) for over 15' !

[The Stationmaster]

On 01/05/2022 at 00:01, Sitham Yard said:

It is perhaps worth pointing out that the 1960 General Appendix was the first General Appendix issued by BR. Before that I think that the GA's issued by the big four remained in force with amendments or supplements being issued by BR. The XP markings appear to have only started in the late 1930's although restrictions on vehicles to run in passenger trains would have been in force before that.

Andrew 

Being horribly pedantic the 1960 General sappendix was actually issued under the imprint of the Railway Clearing House but, interestingly, 'by order of the General Managers ' (of the BR Regions).  The first GA to be issued wholly under BR auspices was the 1972 edition.

 

as far as reference to 'XP' is concerned it remained in the 1960 GA throughout its life, and indeed was mentioned in Supplement No.4 issued in 1971 but no longer appeared in the 1972 issue of the GA so effectively as an Instruction 'XP' lasted from the autumn of 1938, when it was first introduced, to the autumn of 1972.  In the intervening period the Instructions in relation to various wheelbases changed over the years but apart from any specific local exceptions (which would be published in relevant Regional documentation such as a Sectional Appendix) the sole source of the Instruction was the General Appendix.  The only indication used in WTTs - such as the one spade/two spade system used on the WR (and elsewhere presumably?) related specifically to individual trains and whether or not they were prohibited from conveying 4 wheeled vehicles (2 spade) or could only convey 4 wheeled vehicles in excess of a particular wheelbase.

 

However the XP brand was used on all four wheeled vehicles which met the XP specification and this included NPCCS - it wasn't just used on freight vehicles.  the 15ft distinction was, with one exception, used from 1946 when it was stated that henceforth the XP marking would apply only to vehicles with a wheelbase of 10ft to 14'11".  The restriction of speed to 60mph on XP vehicles with a wheelbase of less than 15ft was introduced at the same time, October 1946.  incidentally as originally worded the XP Instruction only applied to vehicles attached to Class A passenger trains, it did not apply to Class B passenger trains where a minimum wheelbase of 9ft was still allowed.  

 

A rather ambiguous change came in May 1950 when the general heading and preamble clearly referred to 'passenger trains' but a sub clause later in the revised Instruction stated that a vehicle with a wheelbase of less than 10ft was not to be conveyed on an express passenger train - so by inference if the wheelbase was over 9ft such a vehicle could presumably be conveyed on a Class B train.  More importantly - perhaps - the XP brand was now restored to ALL four wheeled vehicles and the 15ft distinction in that respect vanished although the speed difference remained (I wonder if the change of branding had ever happened in practice when it came to markings on vehicles?)

 

No further supplements relating to this Instruction were issued for the GWR General Appendix after May 1950 although there were a couple of letters of clarification - which aren't relevant to the Instruction.  Basically the 1960 GA wording is no different from the May 1950 amendment.  There were no significant changes in any amendments to the 1960 GA  until 1969 although in  March1968 an amendment stated that no four wheeled vehicle except one marked XP or P was allowed to run in any passenger train.

 

P.S. Just in case anyone asks - the XP requirements never applied to freight vehicles conveyed on Mixed Trains

 

More detailed change came in May 1969 when secific speeds were introduced fir various vehicle wheelbases - 75mph for 4 wheelers of over 15ft and any six wheeler except milk tanks, 60mph loaded/50mph empty for milk tanks and 60 mph for four wheelers with a wheelbase of more than 10 ft but less than15ft.  Oddly speeds on freight vehicle data panels - which had been introduced in 1968  - were not mentioned and the blanket 60 mph limit still applied.

 

The final change, still mentioning XP and P came inMarch 1971 with, at last, the distinction between NPCCS and freight vehicles with the speed on the latter now being that shown on the data panel.  NPCCS vehicles also underwent some change - 75mph now only being allowed  for those 4 wheelers with a wheelbase over 18ft or for 6 wheelers (except milk tanks). NPCCS 4 wheelers with a wheelbase of 18ft or less were now limited to 60mph.  Milk tanlk speeds were unchanged.  These changes had almost certainly occurred between the dates of issue of supplements 3 and 4 but it would need a search through SOIs (of which I only have a few) to establish a more exact date.

 

Hope that helps clarify things

Edited May 2, 2022 by The Stationmaster
Addendum re Mixed Trains