One of the best aspects of narrow gauge preservation is that the relative small size and affordability of the locomotives means that it is possible to preserve several of each type. Thus, the development of a particular manufacturer's product line can be traced as production evolved over the years. One of the best-known such manufacturers is, of course, Motor Rail of Bedford. They had produced very successful petrol, then diesel, locomotives which had changed little since the First World War. However, the design evolved, rather than transformed. Such an evolutionary step can be seen with the two locos featured in the first of this week's photos - No.40 to the left and No. 14 to the right. No.40 is Simplex Mechanical Handling 40SD516, and was one of the very last locos to be produced, after Motor Rail renamed itself. It is a "40S" type loco. No.14 is one of the earliest 40S locos, works number 22045 of 1959; this loco is named "Knothole Worker". The main design changes on the 40S compared to earlier locos included a fully welded, rather than riveted, frame; this frame is also slightly shorter, to allow locos to be placed sideways into an ISO shipping container for export. 
"Knothole Worker" came to the Moseley Railway Trust from the London Brick Company's works at Warboys, Cambridgeshire. The claypits at Warboys were known as Knotholes, but exactly why is unclear; one suggestion is that it refers to harder parts of the clay deposits, which are like knots in wood.
"Knothole Worker" has not run satisfactorily for a while; investigations showed that it suffered from a badly contaminated fuel tank. This has now been cleared out, and it's now a runner again. As you will see from the first photo, our CME seemed to be intent on reenacting the Torrey Canyon during this process. As ever, we'd love to here from you here.
