Lineside water tanks, sometimes with the water supply being piped several miles was the normal in NSW.
The 'Loco' dam for Lithgow was at a place called 'Dargans' between Clarence and Newnes Jct and the pipe line ran through the 10 tunnels before it reached the Loco depot.
Places like Blackheath and Tarana had an inground brick lined 'pond' or tank and in the case of Tarana, water was pumped from the Fish River to it and then it flowed by gravity to the Tank at Tarana and was also made available to the station and the railway owned cottages as well for domestic use.
The employee who shoveled out the Up Main Ash pit at Tarana also operated the pump on the Fish River.
This was still in use until around 1970 when Diesels finally replaced all steam hauled traffic.
I have no knowledge about Blackheath as it closed with the introduction of the electrification and I was still at school then.