You see the two diverging sets of tracks, locomotive goes off on one so it doesnt destroy the scale, cars go over the other side. This is done to prevent overweight cars from going on lines that are not designed for the weight. Back in the day not every railroad was on a standard rail weight. But this is only one use for weighing cars, there are several others. Surprised to see a surviving scale like that. Most are solid metal now, but that one is wood decked. Id say late 1900s installation. Looks like it was updated at one point.

That's an old scale house. Many (most) things shipped by rail are billed by weight. In addition to making sure the cars are not overweight, shippers of a bulk commodity like coal or grain would weigh the cars for accurate billing for the commodity, and payment to the railroad. I'm not sure where this is, but if there's an old coal or sand mine/facility nearby, that's what got weighed on those scales.

I spotted a lot of grain cars at Bellville Texas and Galveston TX on the scale to be weighed.

Scale house

That is a weigh station that is a set of scales

Just an old scale house I used to sit in one with my grandfather when he worked for Southern Pacific boy those were good days😢

Looks like an old beam scale. I can think of scrap yards that were still using them in the 1980s. Might have a date on it.

Scales,

That's a scale house. They would weigh freight cars on this track.

It's a scale.