Axle Loading for Route Availability less than 3?

[Alex TM]

Hi folks,

 

Can anyone tell me what the axle loading weights were for RAs of less than 3?

 

As I am aware that there were different systems in use according to time and place my particular interest would be in respect of the Southern Railway and BR(S).

 

I've been reading a couple of books lately that have all mentioned axle loading issues in respect of the line they were describing.  Out of curiousity I looked up what the axle loading levels were but I can only find information for RAs of 3 and above.  As I am aware of classes that were rated with and RA of 1 or 2, I wondered what the details would be.

 

I have looked online and can find only information for GWR/WR, LMS/Midland Region, LNER, and BR.

 

Thanks in advance for any help with this.

 

Regards,

 

Alex.

 

 

[The Stationmaster]

What you need is Southern Region booklet No,.  BR 31324 which appeared during BR days.  I've never seen one so haven't got a clue what it contains or how the SR route classification system worked

[watfordtmc]

 

 

The short answer here is: I can’t help you.  However, some rather more lengthy thoughts are below.

 

I believe I’ve read something about this in a past issue of Backtrack, but I can’t find the reference now I‘m afraid

 

It is my impression that the RA concept was first developed by the LNER’s Civil Engineer’s department to provide a more refined means of assessing loading stresses on bridges and that the calculation tried to take account of both the static and dynamic loads.

 

Static loads would the axle weights of, say, an engine in working condition, whilst the dynamic loads would be a mix of both the reciprocating loads – balance weights and connecting rods for instance, and lateral loads – piston thrusts.

 

Consequently, I do not believe there is actually a direct relationship between ‘RA’ and axle loads, although this is how ‘RA’ is commonly perceived.

 

On the specific matter of the Southern Region, @TheStationmaster has drawn attention to the document: Engine Route Availability Book, which listed the various lines of route and which classes were either Prohibited from or Restricted when working over those routes.  Since most things in steam days derived from pre-nationalisation practice, it would seem a safe bet that there was a similar document (or documents) in Southern Railway days as well.

 

I have set eyes (a long time ago) on a Southern Region copy but it did not seem to contain any information on how the restrictions were calculated.  I wouldn’t care to say to what extent the Southern Chief/Regional Civil Engineer took account of the (LNER=not invented here) RA concept – quite possibly not at all in the steam era.

 

There may be a copy of one of these documents in either the National Railway Museum, or The National Archive, but this isn’t a good time for researching!

There doesn’t seem to be a copy in the HMRS archive although you could try an enquiry to one of the Stewards (https://hmrs.org.uk/contacts).

 

Otherwise, you will need either monumental patience watching eBay, or to go through one of the specialist railway book/ephemera dealers to acquire a copy of one of these documents now though.  And expect to pay a hefty price of the privilege.

 

Slightly more accessible would be the book “A Pictorial Record of Southern Locomotives” by the late JH Russell, published by Haynes Publishing when they owned the OPC brand, now, I think, part of Crecy.  This contained weight diagrams for Southern locomotives which would give you the axle load information at least – as long, that is, as you don’t want to know about ex-SECR locomotives.  Very irritatingly, from my perspective at least, the reprographic process has cut-off all the axle loading information for the Ashford series of diagrams, although it’s included for all the other series of diagrams.

The book seems to be reasonably available through the second hand book trade.

 

RA does seem to be a rather quirky concept though.  The reprint of the 1959 ‘Combined’ abc lists, for RA3, engines as diverse as ex GC J10 0-6-0, ex GE J68 0-6-0T, LMS Class 3 2-6-2T and BR Class 2 2-6-2T, although the LMS equivalent of the latter is listed under RA1...

 

If we take engine weight as a very rough proxy for RA, a J10 weighs in at 41 tons 6 cwt (engine only), say 14 tons axle load for practical purposes.  An equivalent Southern engine would be the ex SECR O1 at 41 tons 1 cwt, again around 14 tons axle load.  Yet the O1 was acceptable for work on both the East Kent Railway, and the Rolvenden – Headcorn section of the Kent & East Sussex Railway (KESR).

 

By BR days, engines suitable for an RA1 route would be ex LBSCR A1x, ex SECR P and what we now think of as a 04 diesel.  It was in fact the A1x’s and latterly 04’s that provided services on the Rolvenden – Robertsbridge section of the KESR.  So you are talking of very light railways indeed.

 

(The abc lists for RA1 the ex GE J15, and the diesel classes DJ12 [04] and DJ 15 (03).  Using the engine weight proxy these equate to axle loads of about 12½ tons and just under/just over 10 tons respectively).

 

Regards

TMc

 

[The Johnster]

I would imagine that GW designs that were 'unclassified, any route' would have come under RA1 in the BR system, but the WR more or less ignored it and continued using the coloured spot system.  'Unclassified, any route' included 14/48xx, 58xx, 16xx, and IIRC Dean Goods.  Wikepedia gives the locos weight of the BR standard 2MT 84xxx as 2½ tons more than the Ivatt version, which may account for the RA difference.  

 

Restrictions on individual classes over specific routes might be for reasons other than axle loading. and loading gauge restrictions came into play, as did wheelbase on sharp curvature but this was more likely to be dealt with by a speed restriction.  For instance all locos other than 44xx were restricted to 5mph at North Cornelly on the Porthcawl Branch.

[Alex TM]

Hi folks,

 

Thanks for all the responses.  I have the weight diagrams of the locos that interest me, though that is by chance rather than design.  The dynamic element of RA was something I was aware of after recently reading a book on the North Berwick branch; ex-GNR class N2 locos were used for a while but the local civil engineer was against them as the hammer action of the cylinders was damaging his track.

 

Again, thanks for all the various bits and pieces of fact; they're all interesting.

 

Regards,

 

Alex.

[slilley]

9 hours ago, Alex TM said:

Hi folks,

 

Thanks for all the responses.  I have the weight diagrams of the locos that interest me, though that is by chance rather than design.  The dynamic element of RA was something I was aware of after recently reading a book on the North Berwick branch; ex-GNR class N2 locos were used for a while but the local civil engineer was against them as the hammer action of the cylinders was damaging his track.

 

Again, thanks for all the various bits and pieces of fact; they're all interesting.

 

Regards,

 

Alex.

Alex PM me I have some SR route availabilty books for the whole region covering just about every loco on BR as at 1962. Can probably help you.

[The Johnster]

19 hours ago, Alex TM said:

local civil engineer was against them as the hammer action of the cylinders was damaging his track.

 

All civil engineers are by default opposed to the use of their track by trains, in the same way that all fitters are opposed to locomotives being driven by drivers.  Guards always think drivers are going too fast, and passengers always think they are going too slow (but sometimes complain in the ambulance when they're not).  Storesmen are always reluctant to hand out their goodies (you had a battery for your Bardic last year!)  All are, of course, perfectly correct...

 

Using trains on railway lines is highly destructive to both trains and railway lines, and should never be attempted anywhere by anyone for whatever reason.  

[jim.snowdon]

On 4 May 2020 at 22:56, Alex TM said:

Hi folks,

 

Thanks for all the responses.  I have the weight diagrams of the locos that interest me, though that is by chance rather than design.  The dynamic element of RA was something I was aware of after recently reading a book on the North Berwick branch; ex-GNR class N2 locos were used for a while but the local civil engineer was against them as the hammer action of the cylinders was damaging his track.

 

Again, thanks for all the various bits and pieces of fact; they're all interesting.

 

Regards,

 

Alex.

I wouldn't be totally certain about that, but what may well have concerned him was side forces on the rails, leading to high side wear and/or gauge spreading as a consequence of their being relatively long 0-6-2s. They were known for that in the Kings Cross area, but beyond there, with relatively generous curves, they were tolerable. Gresley did want to design a 2-6-2 for the GN suburban services, but I believe never managed to get it past the Civil Engineer.

 

Civil Engineers' concerns over the same problem were responsible for all of the early Type 4 diesels being forced to have bogies with a leading pony truck. At the root of it was a general lack of understanding about how coned wheels behaved on rails and the consequent wheel:rail forces. If that had been understood at the time, Gresley would have appreciated why his P2s got their reputation for track spreading in Scotland. The pony truck was contributing next to nothing in terms of guiding the locomotive through curves.

 

For a long time, Civil Engineers seemed to think only in terms of the static loads, and of particular interest to them was the weight distribution of a locomotive (the weight per foot run). That will particularly disadvantage a locomotive with a very short wheelbase compared to one of similar weight and axle load with a longer wheelbase.

 

There are also some memorable cases wh re the CE really didn't understand, but because of his power in the railway hierarchy forced the wrong decision. The best known case for is the one involving the Highland Railway "Rivers". They ended up banned and the CME forced to resign although their dynamic loadings were less than those of smaller locomotives of lower axle load. 

 

Jim

[Alex TM]

Hi Jim,

 

Thanks for that.  There's a lot in there that's new to me, particularly around the subject of coned wheels and the P2s track-spreading reputation.

 

As the the Scottish N2 question, I'll go and have another look.

 

Regards,

 

Alex.

[iands]

Engine Route Availability Book - there's a couple of WR (1963)  ones available on ebay.

 

https://www.ebay.co.uk/itm/1963-Locomotive-Route-Availability-x2-Western-Railway-Region-Cardiff-Division/392719818325?hash=item5b6fecde55:g:1AEAAOSwqkxeZUFY

[brack]

10 hours ago, jim.snowdon said:

There are also some memorable cases wh re the CE really didn't understand, but because of his power in the railway hierarchy forced the wrong decision. The best known case for is the one involving the Highland Railway "Rivers". They ended up banned and the CME forced to resign although their dynamic loadings were less than those of smaller locomotives of lower axle load. 

Yes, that and the big Bens actually had a higher static axle load, plus the clans built to replace the rivers ended up much heavier in the track once dynamic loads were taken into account. Newlands was pretty much completely wrong on the whole incident, and chose not to mention any of his concerns until they arrived. Petty and vindictive, however his subsequent career went rather better for him than poor Smith's did, who ended up leaving the industry in spite of producing the best pregrouping 460 outside of the GWR. 

[The Johnster]

Which confirms that petty and vindictive is a good way to advance your career, and Newlands must’ve had chums on the board for this to be tolerated. 

[jim.snowdon]

It may not have been vindictive, but look at the years for which the GWR's Civil Engineer didn't let on to Churchward and Collett the extent to which he had been upgrading bridges. If he had, we might have seen the original Churchward concept for the enlarged Star with the large boiler from the 47xx instead of the Castle and, potentially, no Kings.

 

Jim