the tablet here was a round disc, a bit smaller than a dvd, but thicker. the tablet holder was a hoop that would fit nicely over an arm hung out a window to collect it, like shown in wepns video. we have one at the club that is bamboo with a buckle to put the tablet on. another club im not quite a member of has a couple of exchange machines, but i dont know how they work.
https://en.wikipedia.org/wiki/Tyer%27s_Electric_Train_Tablet
i have seen tablet use in action at a private railway with only one length of track. i dont think they do it very often, since its pretty fool proof. [one track, two engines with either one away at a time]. i think they did it at a special event where they had a tour group coming especially, so went for the whole authentic actions. this didnt have the use of machines, just the drivers handing the hoop back and forth.
