The EBT Mikes are fairly large engines as are the D&RGW K27 and K36. They may not work well on the sharper curves on that Bachman favors.
I agree with all the points above. Why ON30 which is oddball when they have a really nice product that would sell well as ON3. There were no common carrier 30 inch gauge lines in the USA that I am aware of. There were 36 inch (3ft gauge) in most states. The Pennsylvania RR which is noted for large and standard, owned two narrow gauge (3 ft) lins that I am aware. The Washington Waynesburg in western PA and the Ohio River & Western that ran from near Wheeling to Zanesville in Ohio.
And finally I like the EBT mike the best. It would sorely temp me.