I how this may be a dumb question but I was discussing trains with a friend of mine the other day and the question came up of how much diesel fuel does the tank hold. I did have and answer for him but I told him I knew were I could get the answer. Well were else but here on the grestest information soruce but the OGR Forum. I know that not all loco have the same size tanks but a short list from the experts would be appreciated.

It varies with the horsepower of the locomotive and the railroads' plans for it. 4,000 gallons is fairly typical for modern mid- to high-horsepower road diesels. Some intended for longer runs may have 6,000 gallon tanks. According to one source, the DDX40 could be equipped with 8,000 gallon tanks, which were the largest ever used on locomotives. Some railroads have equipped their long distance trains with auxiliary oil tenders -- tank cars which can feed fuel into the locomotive tanks while on the move. I suppose fuel tenders could be strung behind the locomotive one after another until there was no drawbar pull left for payload...

Well I've been on a yard job since 2003 and I haven't paid any attention to the fuel tanks on road engines during that period. But if I recall correctly:
SD40 and U30C = 4,000 gallons
SD60 or SD70 = 5000 gallons
C44 (of all types) and SD70ACe = 5700 gallons

Four axle units usually have substantially less fuel capacity and first generation units had a lot less, like 1500-1800 gallons maybe IIRC.

My SW1500 switcher has a 900 gallon tank I think.

When we were running MU'd fuel tenders in our trains and helper sets those fuel tenders varied from 19,000 gallons to 32,000 gallons.

BN's LMX B39-8's had smaller fuel tanks than the SD40-2's but 900 more HP. As a result they were always running out of fuel on westbounds between Kansas City, KS and Laurel, Montana. Usually on our Big Horn subdivision. The GP50's were just as bad. So those trains got the fuel tenders early on.

Wyhog

railfancwb and Wyhog thanks for the infor just talked with my friend and told him that had answers in 3 hrs from forum members to my question.
He would just like the cost to fill any of them in his pocket.
Wyhog he said he'd be happy with just what it takes to fill that SW1500 tank.

Again guys thanks for the info and have a nice day

One evening, oh so many years ago, I was backing five BN SD40-2s into the elevator track at Hardin, Montana to pick up a unit grain train. One of the elevator employees was standing next to the track and noticed the large fuel tanks. When I made the coupling onto the grain train he was standing right under my cab window. He asked how many gallons the locos held? I said 4 thousand gallons on each one, thus my 5 had a total of up to 20,000 gallons. He was astonished and then asked, "Do you have to pay for that when you fill up?"
"Oh yes", I replied, "I just put it on my credit card".

Even at the then price of perhaps a buck and half per gallon that would be about a $30,000 fill-up.

Wyhog
(starting 4 weeks vacation tomorrow then it is 3 more months to retirement, but who's counting)