Suspect Illinois Central was a close second to N&W in use of auxiliary water cars. And probably for the same reason: not stopping for water accelerated freight train speed and increased tonnage, as starting heavy freight trains was a slow, laborious process, that sapped horsepower. Recall that steam locomotive peak horsepower was reached at a MPH perhaps 10 MPH less then driver diameter. A lot more work was accomplished at that speed.
Numerous pictures are extant showing IC 4-8-2's, 2-10-2's and 2-8-2's with water cars, highballing mainline manifests and coal trains, as well as secondary lines covered by 2-8-2's.
