I noticed that different railroads order different size fuel tanks on there locomotives, some are very small while others take up the full space between the trucks (specificicly GP38’s and GP40’s), and on my model railroad (which is freelanced) I would like to know what fuel tanks would be apropreate. So, my question is, what factors determine the size of the fuel tank on prototype locomotives?
Thanks!
In modern times, just about every rr orders the largest tank available, and that is all EMD and GE offer. Santa Fe on thier GP60M had to put a limit on the fuel level because a full tank would exceed the weight limits.
When railroads first started getting diesels, they got them for specific jobs, just like they ordered steam locomotives. Thus for a short turns over light rail (or low capacity bridges) they would order something like a light GP7 with a small fuel tank. Later on, many of these were rebuilt with larger fuel tanks to improve versatility.
Locomotives are also offered with varying amounts of ballast (additional weight). For example, and Alco C628 could be ordered with a several choices of empty weights between 330,000lbs and over 400,000lbs.
For the SD40-2, EMD’s standard fuel tank was 3200 gallons, but they offered a larger capacity 4000 gallon tank, which is seen on just about all SD40-2’s owned by Class 1 railroads.
Fuel tank philosophy varies by railroad. A short line that is say 25 miles long and its equipment never leaves its rails woudl probably have smaller tanks. Fuel costs money and ties up financial assets. A railroad that runs hundreds or thousands of miles will need larger tanks but even then it may have a fuel policy. BN used tank cars between engines for massive quantities of fuel because they could get it cheaper in certain parts of the country and also because it had some pretty remote operations