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Route Availability/Weight Restriction Categories for the Big Four?


JimC
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27 minutes ago, Wickham Green too said:

Looks like there WAS a degree of official recognition for 'Lord Nelson' & 'King Arthur' class names by 1949 at least. I've found the 'Restrictions applicable...' booklet and attach the cover, first page and a 'typical' class : - 

Thanks for that... interesting that the Southern lists routes against class, and the LM class against routes.

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On 03/09/2021 at 11:23, Wickham Green too said:

But how many of those class names had any official recognition ? ......... yes, on the Southern, what we know as the 'Lord Nelsons' were 'LN' class - which is pretty close - but the 'Remembrances' were officially 'N15x' class, the 'King Arthurs' were 'N15' class .......... moreover, "Remembrance" and "King Arthur" were not the first of their class in any sense. ( Others will comment on other railways, no doubt.)

 

( There was never a loco called "River", "Schools", "Merchant Navy", "West Country" or "Battle of Britain" ! )

 

 

The ones that had the class name on the nameplate....

 

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Just as a thought, does anyone know of a source for RA numbers for current mainline steam. It would be interesting to see how some of the historical restrictions line up against today's much more sophisticated evaluation.

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20 hours ago, JimC said:

Just as a thought, does anyone know of a source for RA numbers for current mainline steam. It would be interesting to see how some of the historical restrictions line up against today's much more sophisticated evaluation.

I know where they should be (on TOPS) but I am unable to access that in order to check.  If anyone does have access ti TOPs you need the current TOPS number to get to where the information should be.

 

When we were planning GW150 (so obviously a good while back from now) we had engines cleared individually - with any restrictions listed - for the specific routes over which we intended to work them/position them.  The biggest problems tended not to be ones of axle weight but physical clearance so we were even having (G)WR 'Red' engines checked over Red routes to ensure they could be safely used.

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43 minutes ago, rodent279 said:

I guess it's conceivable that some locos may have gone up a category, with the addition of air brakes? Or with extra water capacity in the tender, at the expense of coal space?

Possibly, but I was also thinking there could be changes because the actual measurements and basis of calculation has changed. The GWR system was particularly simplistic and although purely on axle load GWR red - eg Castle, Hall, looks to be less than RA6, I wouldn't be surprised if the modern number is rather greater. Also it wasn't completely unknown for locomotive departments to have a metaphorical finger under the scales and report the weights they'd like to have achieved when they built the locomotives! 

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21 hours ago, JimC said:

Possibly, but I was also thinking there could be changes because the actual measurements and basis of calculation has changed. The GWR system was particularly simplistic and although purely on axle load GWR red - eg Castle, Hall, looks to be less than RA6, I wouldn't be surprised if the modern number is rather greater. Also it wasn't completely unknown for locomotive departments to have a metaphorical finger under the scales and report the weights they'd like to have achieved when they built the locomotives! 

The GWR coloured disc system was very straightforward (aka 'simplistic').   But of course in route availability terms it wasn't the full story because physical clearances were treated  separately and beyond that there were of course exceptions in terms of additional restrictions or exemptions (beyond the 'Dotted' routes) to the weight code - hence the lists in the Service Time Tables/WTTs and latterly in the separate Route Availability booklets.

 

The same of course applies with the BR system so for example when the new (ARC owned) rail link to Whatley Quarry was opened in 1975 they told BR what axle weight it could take.  But we still had to cary out a physical test to check clearances and curvature (for which we used a Class 45 loco because they were the worst for minimum radius and end throw).  Using the physical 'does it fit' test meant that any physical restrictions could then be created (there were none) and published.  Basically no different from what had been done in the past although sometimes clearance restrictions came to light 'through experience'  (the polite was of saying that an engine had hit something).

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For all the experience, knowledge and technology at their disposal, BR into the '90s still used the 'if it gets hit, it doesn't fit' approach at times.

There are photos of, I think, Lab 21 'Argus' (a former Mk3 TRUK) somewhere on the SR, with polystyrene blocks mounted around the coach end/door perimeter area.

Being the longest passenger vehicle to run on the network at the time, the Mk3 would be the 'worst case' for radius, end clearance (and centre overhang too, I suppose) c.f. the use of a cl.45 mentioned by Mike.

Edited by keefer
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On 11/09/2021 at 13:45, keefer said:

For all the experience, knowledge and technology at their disposal, BR into the '90s still used the 'if it gets hit, it doesn't fit' approach at times.

There are photos of, I think, Lab 21 'Argus' (a former Mk3 TRUK) somewhere on the SR, with polystyrene blocks mounted around the coach end/door perimeter area.

Being the longest passenger vehicle to run on the network at the time, the Mk3 would be the 'worst case' for radius, end clearance (and centre overhang too, I suppose) c.f. the use of a cl.45 mentioned by Mike.

Polystyrene blocks were used as the 'final check' in certain instances when carrying out physical gauging if things were expected to be rather tight  The Class 373 Eurostar set which went on the gauging trip to Heathrow was fitted with polythene blocks in various places and some of them got squashed although no damage was done to the vehicles themselves - the Class 37s which worked it were 'block free'.

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7 hours ago, The Stationmaster said:

Polystyrene blocks were used as the 'final check' in certain instances when carrying out physical gauging if things were expected to be rather tight  The Class 373 Eurostar set which went on the gauging trip to Heathrow was fitted with polythene blocks in various places and some of them got squashed although no damage was done to the vehicles themselves - the Class 37s which worked it were 'block free'.

When Stanier was designing his 2-6-0s, the Chief Civil Engineer announced a whole list of areas where clearances over the cylinders didn't exist and from which they would be barred. WAS's answer was to fit a Horwich Crab with lead fingers to the new cylinder profile and run it to all those areas specified. Only in a few locations was there an actual clash, so in those places the CME had to modify what we now call the infrastructure.

 

This of course was long before polystyrene had been invented, but the use of lead as the material served the same purpose.

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3 hours ago, LMS2968 said:

WAS's answer was to fit a Horwich Crab with lead fingers to the new cylinder profile

Churchward had done much the same thing when he introduced his outside cylinder standards. A Dean single with a set of dummy wooden outside cylinders was sent all round the system. The lead fingers were a neat touch though. 

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On 03/09/2021 at 13:30, Wickham Green too said:

Looks like there WAS a degree of official recognition for 'Lord Nelson' & 'King Arthur' class names by 1949 at least. I've found the 'Restrictions applicable...' booklet and attach the cover, first page and a 'typical' class : - 

 

IMG_20210903_0001.jpg.caa41d31f998b42184612010b4312f12.jpgIMG_20210903_0002.jpg.e98e1837d6ed6ecc6178a9b52071b85a.jpgIMG_20210903_0003.jpg.2aeda1893b581e70814c5bee79fca1d3.jpg

OK, the 'W' is hardly typical as it's banned from passenger work !

Pleased to see references to Croxted Road Bridge between Herne Hill and Tulse Hill. About 50 years ago, in my Croydon Control days, the South Eastern was in some sort of bother at Hither Green sidings, and unilaterally decided to divert a freight, already coming off the WLL, to Norwood, where it would have been a nuisance. The loco was a Brush Type 4 (47 in TOPS parlance) and a quick look in the loco restrictions showed it was banned over that link, just as those steam locos had been restricted. So I rang the SE signalman at Herne Hill and pointed this out....

 

I think this bridge is also a regular victim of lorry-strikes.

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14 hours ago, The Stationmaster said:

Polystyrene blocks were used as the 'final check' in certain instances when carrying out physical gauging if things were expected to be rather tight

The 317s for BedPan were design checked in the same way by dragging a polystyrene covered mock up through the Widened Lines. 

Further back in time when the electrification of the Birmingham area was getting underway a train from Euston was to terminate at New Street and go ECS to Kings Norton. Camden and later Willesden had a habit of slipping the biggest available engine on so a Stanier Pacific often appeared. Before the diversion to Kings Norton took place a Duchess was borrowed and ran at walking pace through various lines on the Midland side then over the routes to and from the carriage yard. It apparently didn't hit anything so all were happy, although I never saw one run there myself, just Brits and EE Type 4s on the days when I was spotting.

 

Edited by TheSignalEngineer
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22 hours ago, LMS2968 said:

When Stanier was designing his 2-6-0s, the Chief Civil Engineer announced a whole list of areas where clearances over the cylinders didn't exist and from which they would be barred. WAS's answer was to fit a Horwich Crab with lead fingers to the new cylinder profile and run it to all those areas specified. Only in a few locations was there an actual clash, so in those places the CME had to modify what we now call the infrastructure.

 

This of course was long before polystyrene had been invented, but the use of lead as the material served the same purpose.

Great move, to find out the actual clearances, not what was assumed, or was the case decades ago.

I wonder how many loco classes through the years had been refused approval for building, based on outdated infrastructure information?

 

It's like when governments started to use electronic methods of examining the ocean floors and found all sorts of rocky outcrops etc, that generations of well intended sailors, throwing knotted ropes over the sides, had missed!

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