I've seen so many clips over the last ten years that I'm having difficulty remembering what I've seen before. On the principle that seeing something twice won't do anyone any harm and it's better than not seeing something you should, I enclose a couple of links:
http://www.liveleak.com/view?i=72a_1422210439 Includes lengthy sequence of Holt Mk VIII SPG, US railway gun, well-know shots of FT trials in USA, and about 6 minutes of Mk VIII tank trials.
"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.
The Mark IV is 4642, a tank supplied to the USA on 7 November 1918. The film of it trying and ultimately succeeding in climbing the bank is well known, but I've not seen the clip of the crowd around it before.