Walt,
Your 263E engine and tender will run on 031 RealTrax, in fact it will run on Conventional 027, and even pass thru the 027 switches, excepting the big 810
Crane Car.. However it was really designed for O Guage track, infact my fathers pre-production original Lionel 263E work train, came with a set of 072 - 711 switches, right in the Lionel Wooden Box, housing the entire train set.
PCRR/Dave