I've come across this a couple of times recently. It's Egypt, 2'6" gauge (logical) but is listed as Manning Wardle which is unlikely. I do like the feel of the photo with the pith helmets and the chap carrying the dead mouse on a stick under order, 'Simpkins. Move that mouse!'
The canvas cab sheet is a possible dodge as would be a canvas cover over the running gear to allow for all sorts of motive power. Who's not thinking Tri-ang Polly when looking at this?