Tim H Posted April 6, 2014 Share Posted April 6, 2014 According to Xpress Books' volume on the Cornish main line, Plymouth Laira had a small allocation of 9Fs in 1959/60, delivered new to the depot. Photos of 9Fs in the West Country are rare, but I have seen one or two photos of 9Fs on the south Devon main line, both on Summer Saturday passenger trains and fitted fright. Does anyone know if they ever ran into Cornwall, or did they stay east of the Tamar? Link to post Share on other sites More sharing options...
cary hill Posted April 6, 2014 Share Posted April 6, 2014 I don't think they were allowed over the Royal Albert Bridge at Saltash because of various weight/stressing issues. Link to post Share on other sites More sharing options...
Tim H Posted April 6, 2014 Author Share Posted April 6, 2014 Were they any heavier than Britannias, which did work into Cornwall in the 50s? IIRC Kings and 47XXs were the only GWR locos prohibited to cross the Saltash bridge. Link to post Share on other sites More sharing options...
cary hill Posted April 6, 2014 Share Posted April 6, 2014 Were they any heavier than Britannias, which did work into Cornwall in the 50s? IIRC Kings and 47XXs were the only GWR locos prohibited to cross the Saltash bridge. Briefly touched on in this thread http://www.rmweb.co.uk/community/index.php?/topic/45536-cornish-brwr-locomotive-operations-largely-self-contained/ replies 20/21 towards the bottom. Bridge Curve Analysis apparently. Link to post Share on other sites More sharing options...
bike2steam Posted April 7, 2014 Share Posted April 7, 2014 It seems strange as 9F's had quite a flexible chassis allowing it to take curves down to 4.5 chains minimum dead slow ( same as the Brit). The 7 9F's allocated to Laira in 1959 were all diagrammed for freights going east of Tavistock Junction which included both fast, and regular freights going to Bristol, South Wales, London, and the Midlands, there was sufficient other motive power for diagrams to the west. The maximum axle loading on a 9F was more than 2 tons less than the Brit's, which were about 2 & 1/2 feet longer. Link to post Share on other sites More sharing options...
Torr Giffard LSWR 1951-71 Posted April 7, 2014 Share Posted April 7, 2014 ....given the number of axles on a 9F the axleweight side of the RA calculation should be fairly favourable but the minimium curvature aspect of the RA calculation may be a different matter due to the fixed wheelbase of that long chassis. Dave Link to post Share on other sites More sharing options...
bike2steam Posted April 7, 2014 Share Posted April 7, 2014 ... but the minimium curvature aspect of the RA calculation may be a different matter due to the fixed wheelbase of that long chassis. Dave Nope - the combination of flangeless centre drivers, and increased side-play on both leading, and trailing driving axles took care of that. Link to post Share on other sites More sharing options...
Torr Giffard LSWR 1951-71 Posted April 7, 2014 Share Posted April 7, 2014 ....maybe they were specifically allocated to Laira to eliminate piloting over Hemerdon and Dainton? Dave Link to post Share on other sites More sharing options...
bike2steam Posted April 7, 2014 Share Posted April 7, 2014 ....maybe they were specifically allocated to Laira to eliminate piloting over Hemerdon and Dainton? Dave Yes - now you've hit the nail on the head, in the mid to late 50's the GW main-line to Plymouth was very busy, especially during the summer, the requirement was for locos that could tackle heavy trains over the Devon banks with consummate ease to avoid delays, enter the 9F, one of the best, and most successful design of steam locos in this country. Biased - you bet. Link to post Share on other sites More sharing options...
RMweb Gold TheSignalEngineer Posted April 7, 2014 RMweb Gold Share Posted April 7, 2014 How much was their allocation due to seasonal demands? They seem to have been at Laira from the summer of 1959, being reduced to one by March 1960, then 4 being there for the summer of 1960. After that they didn't come back and the steam allocation dwindled rapidly as the diesels took over Cornwall then the rest of the West Country. Link to post Share on other sites More sharing options...
bike2steam Posted April 7, 2014 Share Posted April 7, 2014 Indeed, a typical example of a good design coming too late, as the last member of the class entered traffic the reason for their very existence was rapidly diminishing, as in the West Country with those having faith in the all conquering diesel hydraulics. ( Walks away with an evil laugh !) Link to post Share on other sites More sharing options...
Tim H Posted April 7, 2014 Author Share Posted April 7, 2014 Tbanks for the responses everyone. My conclsion is that a Modellers' Licence will be required to ruun one of the forthcoming batch of Dapol 9Fs on a layout supposedly set in Cornwall. Link to post Share on other sites More sharing options...
DCB Posted April 10, 2014 Share Posted April 10, 2014 Tbanks for the responses everyone. My conclsion is that a Modellers' Licence will be required to ruun one of the forthcoming batch of Dapol 9Fs on a layout supposedly set in Cornwall. Go for it, plenty of people run the Peco 2251 on lines supposedly based in Cornwall... Link to post Share on other sites More sharing options...
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