Go to 1st series Vol.XXIII Chapt.XXXV pages 582-583 its a report of Col.William P. Innes 1st Mich. Eng. . He was ordered June 23,1863 to repair tracks etc. left Murfreesborough June 29. It doesn't say anything about dynamite.Two bridges were partially burned. You judge if this is what you are looking for.
Same Vol. and Chapter pages 324-325 mentions an attack on the Louisville & Nashville RR.Apr.1863 Again No dynamite.
Railroad destruction and repair are common occurrences throughout the war. As I said In Middle TN. the 1st,. Mich. Eng.& Mech. would of had a part.

http://digital.library.cornell.edu/m/moawar/waro.html