"Sometimes things that are not true are included in Wikipedia. While at first glance that may appear like a very great problem for Wikipedia, in reality is it not. In fact, it's a good thing." - Wikipedia.
I hope there was plenty of petrol in the tank, or it might have been difficult to restart the engine at that angle, given the likelihood of gravity feed being in use.
The truck is an american built Pierce Arrow, but it has been converted to carry an artillery piece as can be seen by the hole in the back of the cab and the extension on the roof (making it a "portee"). Still in use at the start of WW2.
The Weald Foundation's new website (it must have been a trial site as it now says "coming soon") indicated they have recently acquired a complete Renault tractor and, for good or ill, robbed the mechanicals for one of their FTs.