As with the full-sized engines, the low pressure inside cylinder drives the leading driving wheelset with valve actuated by slip eccentric gear, the two high pressure outside cylinders drive the rear wheelset, their valves mounted underneath the cylinders, actuated by Joy gear.
The engine rolls freely but runs erratically on air, the inside and outside cylinders disagreeing on exactly which way they should be going (which aparently was not unknown in the full size engines). The regulator leaks and one clack on the backhead is missing its pipework.
Boiler was structurally sound on hydraulic test at 160psi for 80psi working, although with a couple of minor leaks from stays and one tube showing slightly damp at the firebox end.
Paintwork is dreary, a pale imitation of the original polished Blackberry Black LNWR livery!
| gauge | 3 1/2 inch |
| length/inches | 23 + 15 |
| width/inches | 6 1/2 |
| height/inches | 10 1/2 |
| weight/kg | 18 + 6 1/2 |
| wheel material | cast iron |
| axlebox type | plain bearing |
| cylinder material | gunmetal |
| valve type | slide |
| valve gear | Joy + slip eccentric |
| reverser type | screw |
| lubricator type | mechanical |
| injector(s) | 1 |
| working pressure/psi | 80 |
| boiler type | locomotive |
| boiler material | copper |
| boiler construction | silver soldered |
| superheater(s) | 2 |
| superheater type | flue tube |
| safety valve(s) | 1 |
| safety valve type | spring |
| hand pump | 1 |