The three guys behind the truck (and dark haired guy partially visible to the left of the left ramp) appear to be in motion, having just finished hand-pushing the truck up the ramp (in concert with the driver accelerating the engine, no doubt). Note the blurred legs and the body positions. My guess is they helped the truck get the wheels up and over the chock.

So, the truck had plenty of forward/upward momentum when the shot was taken, and they were in little to no danger of the truck rolling back on them.

The structure is a gantry from which a winch and pulley could be attached to hoist cargo at this "team track." More modern versions would include a crane on the gantry.

Agreeing with bewswain and looking closely at the picture and the angle of the rear axle, the rear right wheel looks to me as thought it's actually on TOP of the chock that one assumes is there to stop it rolling backwards!

Personally, I would not be standing between those ramps, where you couldn't even jump sideways to get out of the way if it started to roll. Ouch.

---

Washington Post, September 21, 1919.

Washington Junior Marines and Naval Scouts in Training Camp.

by Aunt Anna

The newest organization for the training of young Americans opened its first training camp Saturday, September 6, at what was formerly the camp of the National Service School, on the Little Falls and Conduit road about halfway between Georgetown and Glen Echo.

The camp is known as Camp Barnett in honor of Gen. Barnett, the head of the United States marine corps. The organization is sponsored by Mrs. Barnett, and the object is very much the same as the Boy Scouts, namely to teach the boys manliness and patriotism.

Sergt. Al Krieger, of the Thirteenth company, Tenth regiment camp of Quantico, Va., was detailed to instruct the boys and command the camp. They were taught infantry drill, calisthenics, signaling, both radio and visual (wig-wag and semaphore), grenade throwing, trench warfare, personal and camp hygiene and the traditions of the marine corps.

About 50 boys attended the first camp which lasted a week. Not all the boys were equipped with uniforms but their interest was none the less. …

This looks like they are practicing loading vehicles onto railcars.

One of the other LOC photos, Call Number LC-H261-30881, of "Junior Marines" from 1919 shows the flatbed railcars, but it does not show these trucks. It does show a similar trailer on the railcar and has similar bricked surfaces on both sides of the train tracks. A low resolution picture of this photo is below.

As a truck driver in the Army we used similar ramps to drive our 2 1/2-ton and 5 ton trucks onto a row of flatbed railcars and then tie them down for transportation. The railway takes the trucks to a shipyard for loading onto a cargo ship.

Finally, the Baltimore and Ohio Railroad trestle seems to confirm that this is a railheading operation.

Since the lettering on the overhead structure reads Baltimore and Ohio Railroad, I suspect that the trucks are being loaded on railroad flat cars the same way the circus does, but without the help of elephants.

Wanna go stand behind that flimsy overloaded truck on a steep ramp with me?