Never repaired a railway track. Did try some thermite for fun, burned through a piece of half inch mild steel plate. What really impressed me was how bright it was. It was tough to ignite but using a piece of magnesium as a fuse got it going.
Have painted cars, one panel at a time with a 3/4 hp unit but with a 30 gallon tank. One panel at a time is no real problem if you are doing non metallic. Had a neighbor that sprayed cars using a half hp comp. and a 50 or 60 gallon tank. Big enough tank, don't need a high hp comp.
When i bought my 69 barracuda coupe the dist. was set at 5 degrees retarded, pinged a lot when advanced, turned out the heat riser valve was stuck on CLOSED. Engine temp.gauge showed normal, but the intake must have been very hot.