Noticing the outfits on some of the people in the background... on the train platform. Seems more like something worn around 1910... curious. Based on that added detail, I found that the train station in Nampa is now a museum.

I love spending time in train stations converted to museums. A favorite pastime as spring approaches!

A half hidden loco stands left of the bunker. This is equipped with a Vanderbilt tender, which looks almost like a tank car from this perspective. But tank wagons usually do not have big headlights and no coal box on it. And if you look closely, it could be that behind the coal chute - where the locomotive's chimney might be - the air flickers a little bit.
Maybe the middle of the cabooses has its best time behind it - or the track situation on this point is not the best.

The smokestack visible further down the tracks appears to be the Nampa Train Depot which is now preserved as the Canyon County Historical Nampa Train Depot and home to the Canyon County Historical Society.

https://canyoncountyhistory.com/

By measuring the rail width at the shadow of the tower, the tower would be 34.8 feet tall, which would give a runaway rail car speed of 32.2 miles an hour after rolling down the hill. Less destructive than you might wish for.

Thanks, damspot, for your very informative reply. Your response answered the questions I was considering asking, except for one:

What is the purpose of the tall, narrow tower in the background? I'm guessing it's some sort of water tower?

This shows Oregon Short Line 3055, a Union Pacific CA-class caboose built in 1911 and retired in March 1953. Behind it is a much older NCS-class caboose built about 1901 or before.

A few RR's like the Nickel Plate, New Haven and Union Pacific, added a third marker light on the roof of the cupola. ICC safety inspectors were always lavishing praise on this practice as many rear end collisions avoided by the light being higher up and easier to see from a distance. Now we have that feature on our automobiles.

The coal-laden cars are pulled upward by a cable to the top here, and the rollers on the centerline of the ramp's track are to keep wear on the cable and the ties lowered. At the base, where it levels (?) off, there is what is known as a derail. This is a section devoted to intentionally divert a car to the ground if it runs away in the event of a cable breaking or the connection comes undone. The cars are fed onto the ramp from the track leading away at the left of the photo. Good detail picture of how the railroad solved a potential saftety issue.

Roster of Union Pacific Wooden Cabooses

Oregon Short Line Wooden Cabooses - Class CA
Car Number OSL 3055
Date Built Jan 1911
Length 30'
Builder AC&F
Previous Type
Previous Number OSL 700
Date Renumbered Jun 1916
Date Retired Mar 1953
(Later that summer, I took a train from Jacksonville, Florida to Washington, DC as a proud member of the School Boy Patrol.)
Notes

In 1913, construction moved from wooden to wooden with steel under-frame and class changed to CA-1

Here is a link to the home page that looks to include almost every unit of Union Pacific rolling stock.

http://utahrails.net/index.php