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jim.snowdon

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  1. I am not going to dispute your experience, but I have seen some of those markings on premises, although not, I suspect, in relation to any potential for burglary. They have been, from memory, on licenced premises and reputed to be Travellers' marks relating to what sort of welcome (or not) lies within.
  2. The patches on PO wagons emerged as a wartime measure when, due to repairs, the wagon's painted number had been expunged by repairs. Later, as they were renumbered it would have provided a ready means for obscuring the old number and thus avoiding confusion.
  3. A key point is that the RCH drawings do not define what you had to build, only what you could build if you wanted to avoid having to get specific approval from the RCH wagon committee. If a customer wanted, they could have, say, an 18T 6-wheel mineral wagon with drop sides, but before it could be registered, the design would have needed scrutiny by the Wagon Committee. The virtue of the 'standard' wagons was that their designs were effectively pre-approved; all that the resident Inspector at the builder's works needed to do was confirm that they had been built to the design and that the materials and workmanship were up to the required standard. The real purpose of the RCH was, first, to set minimum design and maintenance standards so that wagons were up to a standard that would not put at risk the operation and safety of the railways over which they ran. That originated from a series of railway accidents involving poorly built and/or maintained private owner wagons over which the railway companies had relatively little control. The other significant purpose was that it allowed the standardisation of all the major components, which would have simplified the process of getting wagons maintained and repaired. Parts, particularly in regard to the running gear, became interchangeable and easily obtained without the delays and costs incurred in having to send off to the original builder for parts that were non-standard. There are RCH drawings for 10' wheelbase underframes for merchandise wagons, dating from the 1920s, so the option was there for a 10' wheelbase coal wagon if anyone had wanted one. That there aren't any really only indicates that the coal mining industry didn't want them, potentially, I would suggest, because the 9' wheelbase coal wagon had become entrenched in the industry's infrastructure, in regard for example to wagon turntables, tipplers and traversers in coal depots, coupled with there being no purpose to changing from the established 9' wheelbase.
  4. It would be interesting to know, but I wouldn't be surprised if it was simply a case of infringing the 75mm electrical clearance that is, in any case, a nominal figure going back to Ministry of Transport days (when it was 3"). You have to get a lot closer than that for 750V to be tempted to flash over. (In my LU days, we occasionally got brushgear to frame flashovers on the LT118 motors on the D78 stock when it went onto BR metals, and they were always between the sharp corner of the opening in the motor frame and the corner of one of the brushgear bolts. As far as we knew, they never did it twice as the arc rounded off the sharp corners on the bolt heads. That gap was nominally 19mm (3/4"). Jim
  5. Or, a standard type from one of GEC/Metrovick/BTH or EE? Some technology changes remarkably slowly, applying the if it ain't broke don't fix it maxim.
  6. No, but they did use recycled EE507 traction motors from the 4EPBs and later SR EMUs. The EE507 became a more or less standard motor on the Southern, with the EE546s on the REPs and the 73s.
  7. Well yes, up to a point, I think. Certainly the 9' wheelbase 4-wheeler was not accepted as a competent vehicle at anything like passenger speeds, but if the application of XP markings is anything to go by, 10' wb was. I appreciate this might have been optimistic, given that the LNER increased the wheelbase of its fish vans to 12'. Equally, I appreciate that in that day and age, very little of substance was known about why vehicles would become unstable at high speeds; in fact it appears to have been something of a non-issue until certain BR 4-wheel wagons in particular started to routinely derail at high speed on long welded plain line that anything serious was done about finding out why. Either way, the rules say that two four wheel vehicles with at least 10' wb could be coupled behind the brake van and, if XP classified, run at passenger train speeds. Stuck at the tail end of a train, the riding qualities of the last vehicle(s) weren't really affected by the number of vehicles ahead of them, with the only restraining factor being any frictional damping across the faces of the buffers. If any vehicle was going to have a sufficiently unrestrained ride to derail, it will be the last one, and derailment is derailment. On that basis, I'm yet to be convinced.
  8. From a purely engineering consideration, having two different rules for passenger rated vehicles and freight vehicles makes no sense. It's the continuity of the brake pipe that matters, and making certain that any piped vehicles are inside the consist. So what was behind there being two rules?
  9. The top manholes on the 100T tanks were placed so as to be at the same centres as those of coupled pairs of 45T tanks.
  10. True, although with what we know today about wheel/rail forces, unknown then, the lateral forces on curves can be very significant, as can the effects of centrifugal force when running at elevated rates of cant deficiency with both conventional and tilting trains. That, however, is another subject altogether.
  11. Interesting. How would you describe the broad gauge as technically flawed? The engineering all worked, and as far as I have seen, worked quite well. Its real weakness was at the interfaces with the other standard gauge railways (of which there were rather fewer in the 1830s and 40s.
  12. Very probably, but the writing had been on the wall ever since the decision by the Gauge Commission favouring 4' 8.5" gauge, and removal of the broad gauge had started a good twenty years earlier. The original decision to adopt broad gauge was sound enough at the time, but what could be argued as technical excellence was swamped by the sheer quantity of standard gauge track that was built. Shades of Betamax and VHS many decades later.
  13. Possibly, although as there aren't many photographs of gauge conversion, there isn't much to go on.
  14. Or in the period running up to the gauge conversion. quite often preparatory work was undertaken to include narrow gauge into parts of broad gauge layouts in order to facilitate the changeover, which primarily concerned the miles and miles of plain track. For pointwork, it is simpler to add the narrow gauge rail and timbering before conversion than it is to actually convert a turnout on the ground.
  15. It couldn't be any more embarrassing than having signals fall across the tracks on account of the pole having rusted through at the base.
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