Re: Numerical Mysteries

James,

When the southern railroads changed from 5-foot-gage to 57”, I assume that this was considered a move to become standard gage which was officially 56.5” at the time of the adoption. Therefore the southern railroads would have 56.5”-gage wheels running on their tracks as interchange traffic, no matter what they did with their own wheels. So, I assume that southern railroads adopted the 56.5”-gage wheelsets like all other railroads.

Was the southern railroad adoption of 57”-gage track done just to allow an extra ½” play in the relationship of track to wheels?

Was that the motive for PRR building 57”-gage after 56.5” was adopted as standard gage? Was the extra ½” preferred for better tracking through curves, or were there other reasons?

Are the ex-PRR lines today 57”-gage? What about Strasburg?