This loco looks conventional at first sight, but a second look shows six coupled driving wheels under the tender, which in fact carries a turbine power plant. The tender also carries the condenser, which permits direct coupling to the turbine exhaust through a large area. This is essential to get the best efficiency from a condensing turbine.

The loco was built by Beyer-Peacock of Manchester, UK, the turbine technology being provided by Ljungstrom Anturbin of Sweden.

Left: A very rare photograph of the turbine unit. The turbine had a single impulse stage followed by 18 rows of reaction blades. Its design power was 2000hp at 10,500rpm, corresponding to a speed on the rails of 78mph. Design steam conditions were 300 lb/sqin at 200 degC superheat. The large rectangular cross-section exhaust duct can be seen leaving the turbine assembly at the right.

The smokebox contained a rotating-media air preheater warmed by the flue gases. The funny sector-shaped thing on the front of the smokebox is the drive to the friction rollers that rotated the air preheater.
Since there was no steam blast, a forced draught fan was used, coupled to the preheater rotating machinery.

This loco ran on the LMS 1926-28, but was then withdrawn and eventually dismantled. Great things had been expected of this courageous design, but results were not good, partly due to condenser air-leaks, but mostly down to poor combustion.

The design raises an obvious question; surely it is inefficient to have none of the weight of the locomotive available for adhesion?

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