JJ73 Posted July 10 Share Posted July 10 Sorry I meant to ask this last night but just didn't get around to it... I have got these 2 Locos & they both look the very same to me... A) R3990 LNER Class A1 4-6-2 'Doncaster' No. 2547 & B) R30216 LNER Class A3 4-6-2 'Harvester' No. 2573 ...& please don't say that 1 Loco is an A1 & the other is an A3 or different names or Running Numbers cos that doesn't really mean a lot to me!!! Because They are both 7P6F (Not sure what that means either!!!???!!!) Thanks in advance 🙂🚂 Link to comment Share on other sites More sharing options...
What About The Bee Posted July 10 Share Posted July 10 7P6F P = Passenger F = Freight The higher the number, the stronger the locomotive 7P means seventh category of strength for Passenger 6F means sixth category of strength for Freight Link to comment Share on other sites More sharing options...
atom3624 Posted July 10 Share Posted July 10 For the models I've seen that they both have diecast running boards / footplates and a flickering firebox - so both are the latest specification. Al. Link to comment Share on other sites More sharing options...
ntpntpntp Posted July 10 Share Posted July 10 @JJ73 If you do an internet search on the differences between A1 and A3 locos it will tell you (an upgraded boiler and other modifications). Link to comment Share on other sites More sharing options...
JJ73 Posted July 11 Author Share Posted July 11 Thank you all - That makes sense 😉🚂 1 Link to comment Share on other sites More sharing options...
JJ73 Posted July 11 Author Share Posted July 11 The main difference between an A1 loco and an A3 loco is the boiler pressure, 180psi for the A1s and 220psi for the A3s. This leads to an increase in tractive effort from 29,835 lbf to 36,465 lbf (when both classes had 20in by 26in cylinders)1. The A3s also had an increased superheated surface as more flues were added1. The cover plates are the main external distinguishing feature between the A3s and the A1s2. With the advent of the A3s, all new Pacifics were built to the A3 specification rather than the A12. 1 Link to comment Share on other sites More sharing options...
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