This is a fairly specific question and relates to a 4-4-0T with BP 120 psi and 480 gallon tank running a semi suburban type service on a 15 mile line hauling 7 4-wheeled coaches with 4 intermediate stops and taking 1 hr 15 minutes. The question is, how often would it need to take water? The reason is , we are researching a long gone line but photographic evidence shows no signs of water tanks or water columns other than at the shed. My own opinion is that it could easily do a round trip without refilling and perhaps a second round trip also? Later the line was extended 7 miles in the other direction, again no evidence of addition water being available. Two trains were in use. I can provide more details if needed.