Murph,
The short answer to your question based on my experience with the maintenance and operation of steam locomotives on several different tourist railroads is NO.
The cost of labor varies widely from location to location. Labor makes up the largest percentage of the total cost. If those costs are accounted for there is still the issue of the operating terrain to be considered. Mountainous territory uses up fuel and machinery more rapidly than flat country. There is also the question of tonnage being moved. The harder the locomotive works the more it will cost to run. However a large locomotive pulling a light train on level track may well still cost more to run than a small locomotive pulling a load closer to its maximum capacity.
I hope this helps answer your question.
John Bush