John Hutchings, of the Industrial Locomotive Society, kindly sent me a copy of a very interesting letter recently (September 2011).
Recall that Sentinel 7109 was the first of a series of eight pre-war double engined Sentinel locos with the unusual curvaceous profile. Being a first-off, its performance needed to be marketed to potential customers and so it was delivered to the LMS at Newton Heath, Manchester for evaluation.
The letter below describes the tests and shows how impressed the observers were with 7109 at the start of 1928. (Click the picture to enlarge it for reading).
|Sentinel 7109 performance|
(Letter courtesy of John Hutchings, Industrial Locomotive Society).
(Note: this was retyped by JH as the original is in poor condition).
Clearly, you can do quite a lot with a 200 HP loco so long as you don't want to do it too quickly!