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2 1/2 inch gauge "Ursa Maximus" 4-8-2 - stock code 10353

We're indebted to Bill Edmonson who has kindly pointed out that "Uranus" is actually "Ursa Major" - designed at around the same time, by the same Joslin/LBSC partnership.

A part-built 2 1/2 inch gauge 4-8-2, based on the Joslin/LBSC design for a three cylinder 4-8-2 "Mountain" locomotive.

James Joslin of Canada and LBSC had a long-running correspondence; prior to "Ursa Maximus" he had commissioned the 4-8-4T design which was to become "Helen Long", published in 1927. LBSC described the new design as "A shock for Swindon"!

Work to date is to a good standard, and comprises:

  • Rolling chassis with coupling rods, motion brackets and expansion links, crank axle, centre cylinder erected
  • Outside cylinder assemblies machined, complete with pistons, valves, rods and guides
  • Quantity of valve gear, including radius rods
  • Smokebox assembly, machined chimney casting
  • Combustion chamber boiler
  • Eight wheel bogie tender with hand pump

Still plenty of work to do, but an interesting and, nowadays, very rarely seen model ("Helen Longs" aren't much more common either, we've had one complete engine and two part-builts in the last twenty years).

A large locomotive, it weighs in at just over half a hundredweight in its current state. Copies of the original drawings are still available from the National 2 1/2 inch gauge Association.

gauge 2 1/2 inch
length/inches 32 + 21
width/inches 5 1/2
height/inches 8
weight/kg 26
wheel material cast iron
axlebox type plain bearing
cylinder material 3 x gunmetal
valve type piston
valve gear Walschaerts
reverser type pole
CE mark n/a - non-commercial
boiler type locomotive with combustion chamber
boiler material copper
superheater(s) 2
hand pump 1