Decal placement

Most of the time the placement of these labels are railroad specific,

I model the SP/SSW and they only use one 600 Volts label on the access door by the generator (both sides) one Fire Extinguisher label on the engineers side by the sight glass (2nd Gen units). 

The fuel fill label was not use much after the late 60's early 70's.  If they were used they faded quickly and you can't really see them without a magnifying glass.

You could add a builders plate decal and an F for the front of the unit.

Andy H

as above

They're usually quite railroad specific (because the roads often ordered different options) and they are sometimes period specific even on a given road and model. For example, things like fire extinguishers might be relocated, either by shop forces or at rebuilds, etc. Probably something like 600V would stay put since that's related to the location of the generator, which is usually the second largest single component in a diesel electric locomotive. The F for "front" might change on a given locomotive if the road changed policies, or if a merger or takeover occurred, although this often required some physical changes in the cab to effect.

Usually you will need to refer to the official painting diagrams of the railroad in question. For example, C&O had official diagrams and they are still on file at the C&O Historical Society. I've seen the N&W ones reprinted in a book on N&W 2nd generation diesels. Etc.

Great, that gives me a lot of

Great, that gives me a lot of freedom, since I'm modeling a freelance road. It's accurate if I say it is.  Thanks!

F

Technically the only lettering required by law on a diesel engine is the F to mark the front.  Pretty much all the other lettering is optional.

Federal Locomotive Marking requirements

https://www.ecfr.gov/cgi-bin/text-idx?SID=58a46adf5b9adf23d4f0eb9e6136e076&mc=true&node=pt49.4.229&rgn=div5#sg49.4.229_161.sg3

§229.85   High voltage markings: doors, cover plates, or barriers.

All doors, cover plates, or barriers providing direct access to high voltage equipment shall be marked “Danger-High Voltage” or with the word “Danger” and the normal voltage carried by the parts so protected.

Additionally emergency fuel exterior cutoff valves ,

§229.93   Safety cut-off device.

The fuel line shall have a safety cut-off device that—

(a) Is located adjacent to the fuel supply tank or in another safe location;

(b) Closes automatically when tripped and can be reset without hazard; and

(c) Can be hand operated from clearly marked locations, one inside the cab and one on each exterior side of the locomotive.

Snow plow markings

§229.123   Pilots, snowplows, end plates.

(a) Each lead locomotive shall be equipped with a pilot, snowplow, or end plate that extends across both rails. The minimum clearance above the rail of the pilot, snowplow or end plate shall be 3 inches. Except as provided in paragraph (b) of this section, the maximum clearance shall be 6 inches. When the locomotive is equipped with a combination of the equipment listed in this paragraph, each extending across both rails, only the lowest piece of that equipment must satisfy clearance requirements of this section.

(b) To provide clearance for passing over retarders, locomotives utilized in hump yard or switching service at hump yard locations may have pilot, snowplow, or end plate maximum height of 9 inches.

(1) Each locomotive equipped with a pilot, snowplow, or end plate with clearance above 6 inches shall be prominently stenciled at each end of the locomotive with the words “9-inch Maximum End Plate Height, Yard or Trail Service Only.”

(2) When operated in switching service in a leading position, locomotives with a pilot, snowplow, or end plate clearance above 6 inches shall be limited to 10 miles per hour over grade crossings.

(3) Train crews shall be notified in writing of the restrictions on the locomotive, by label or stencil in the cab, or by written operating instruction given to the crew and maintained in the cab of the locomotive.

(4) Pilot, snowplow, or end plate clearance above 6 inches shall be noted in the remarks section of Form FRA 6180-49a.

(5) Locomotives with a pilot, snowplow, or end plate clearance above 6 inches shall not be placed in the lead position when being moved under section §229.9.

[77 FR 21347, Apr. 9, 2012]

Also in addition to Federal regs , if the railroad is insured , the insurance company can require addition markings .