Overland models N&W A 2-6-6-4 S gauge

Photos would help. 

If it's what I'm thinking of however, those would be drains for the tender deck so water wouldn't accumulate.

Rusty

After reading your post I looked at a few pictures and videos online to see if the prototype engine, or a detailed model, would indicate what they could be for. These pictures show something that looks like lift rings at the rear of the tender on the top surface in the two corners. Perhaps someone more familiar with steam engines can identify what they are.

Dean

I would still go with drains for the tender deck.  The design would be to try to keep objects from blocking the drains.

Rusty

never thought of drains.......makes since .........I was in Roanoke last Saturday I should have gone to the transportation museum and climbed up the 1218 tender for a look see.......

Jackie

In the first photo, they appear to be curved vent pipes...possibly to let air escape?

Check with the N&W Historical Society.

The tank of a tender is hardly air tight.  The water hatches, even when closed provide all the ventilation needed.

Rusty

Those are definitely water drain holes for the top of the tender deck, for when the Fireman or laborer overflows the water portion from the stand pipe. Many. many steam locomotive tenders have such drain holes.

The reply from the Virginia Museum of Transportation:

The area to which you are referring is an air vent. When water would drain out of the tender, if you didn’t have a vent to allow air into the tender you’d end up with a vacuum which could collapse the tender like a soda can being crushed in the hand.