Hello 'Botanybay' (perhaps, give us a clue, of a name?) Welcome to the Forum. A sense of humour is optional, but really useful!
The LGB-stuff (and other makes) is based on metre-gauge European railways, so works out at 1:22.5.
LGB made a decision that all their stock would cope with the infamous 'R1' radius track, so to make everything look 'right' together, some dimensions, of some models are wrong..
We tend to use 1:24 diecast vehicles, and the like, but it really depends on how much it offends your eye. - If it looks right to you, then it is right.
Give us a clue what sort of rolling stock you have, and we can tell you more.
Oh, and the Grandchildren will not notice, or care!
PhilP.