That 1/6 Sherman was a James Desimone roto-mold tank he offered back in the late 90s. It was very basic and some of the parts like wheels and bogies had to be redone/scratchbuilt by me, the tank treads were from another vendor Steve Hoeger. It probably weighs in at 25-30 lbs, it's more awkward to carry than heavy. It does roll but I never put a RC unit inside but I did put in seats for the 5-man crew. The turret sits on a 12" lazy susan ball-bearing turntable to give you an idea of how big it is.
If you think our 1/48 scale trains take up room try housing a dozen or so of these 1/6 vehicles, you see in that video they're in a field at a guys "manor" in England, the detail on their vehicles is first rate (they have access to actual drawings and vehicles). Jerry, I also have one of those RC Stuart tanks, actually 2, one I converted to a M8 HMC Scott (Howitzer Motor Carriage).
Lets' just say I have enough 1/6 figures to stage a coup or invade a small country, most of them are boxed up now but I have all my tankers and pilots on display on lower shelves in the train room. Military stuff has always been a part of me, my parents and their siblings all took part in WW2. I even have a figure that looks a lot like my dad (9th Air Force).
I thought I had a pdf manual showing how they secured tanks and vehilces on flat cars but I can't seem to find it, probably on a CD I made.