My memory on the exact issue is as rusty as an old Kanawha. Probably in the mid-sixties, early seventies. I gave up reading MAD around that time.

Could someone elaborate on how these fuel line heaters were configured? Are we talking something along the lines of heat tape wrapped around the fuel lines or something else?

Fuel heaters on GE U-series locos are (were) a closed-type heat exchanger, very similar to a small Elesco feedwater heater "tube bundle". The fuel heater has four connections at the headers- fuel in and fuel out, engine cooling water in and out.

Engine water at 160-180 deg circulates to keep the fuel warm. These were usually installed on the suction line from the fuel tank. After the fuel heater, fuel went to primary filter/strainer, then to pump, then to secondary filter, then to fuel supply mainfolds.

The fuel heaters look like (and may simply have been) Vapor #525 "wash water heater" used on passenger cars to heat domestic water, using trainline steam.

Most diesels have the fuel return to the tank located right next to the fuel suction intake. This helps give some "warm fuel" right to the suction line, it can help when temps drop and fuel starts gelling.

Well, we're certainly far afield from C&O 614....

Howard P.
Pour Point, NC