@Mallard4468 posted:Here are side-by-side pics of similar billboard reefers in HO, On30, and O.
On a recent tour of the East Broad Top, it was mentioned that the EBT cars are about 3/4 the size of standard gauge cars. Note that the EBT was 3-foot gauge, not 30", but I think that's because they couldn't buy HO track when it was being built.
For size comparison, here's a re-post of some of my earlier photos - the largest car is an MTH Premier billboard reefer, the orange car (in the middle in both pics) is a Bachmann On30 reefer, and the smallest car is an HO model. You'll notice that the On30 car is only a bit larger than the HO car, despite the fact that it is indeed O scale.