I expect the friction coefficient to be the same, as it is both steel that the wheels are running on and I think they use the same kind of paint for it. I do think the IBox is stiffer and therefore less vibration will occur which will increase the speed, call it a lower practical friction or so
At Mechanical Engineering I learned that it is much stiffer to have the cross supports go through the main support. The forces are then divided over two walls, with just one it might fold/buckle. I'm pretty sure the supports are thus going through, the ladder is of course less important than the...
It doesn't look like they are doing that. I also doubt if you could stick a footer to a plain concrete floor, does not sound very strong to me.
Anyway, nice that there's track on site, hopefully it goes vertical soon
It is still for sale on here, but maybe the site needs to be updated.
It was added today on RCDB as being a surfrider instead of a half pipe coaster: https://rcdb.com/18252.htm
I don't know where they have that info from.