I went to the Fullerton Train Museum
It was neat! I've meant to do this for a while but it's only open twice a month (1st and 3rd Saturdays, I guess) and even then only from 9am to 12 noon, so it'd always slip my mind.

The reason the hours are so limited is because it's run entirely by volunteers from the Southern California Railway Plaza Association. So the staff is like, a bunch of old dudes and their cool wives while the clientele is mostly parents with small children who can't read the "Do Not Sit On This Very Old Furniture" signs. The old lady who toured us through the cars was very nice and very patient with the small children and the senile seniors! These people fucking love trains! Good for them!
Most of their train cars are from the 1940s. The tour guide was particularly enthused about the cabooses, one of which dated back to 1929. Another from 1942 was referred to as a "War Baby" caboose because, as steel was being requisitioned by the government for the war effort, the interior was made entirely of wood. They all had big old coal stoves and huge metal tanks where staff would store drinking water. Neat!

I'd never thought about what a caboose was actually for, which turned out to basically be a multi-purpose office space. The guide put a lot of emphasis on each one's cupola (this windowed lookout section), where crew members would basically climb up and keep an eye on stuff from higher up to make sure things were running okay. As our guide put it, eventually these got phased out partly because cameras and sensors for that information became available and partly because the rail companies didn't like having a car attached that didn't make them money.
Besides those, there are pretty mundane lounge and sleeper cars that have all the things you would expect them to have. There are a bunch of little design quirks with otherwise normal objects that are made to facilitate use on a train that'll be shaking around a lot; for example, all the griddles and stoves in the kitchen have lips on them so that nothing slides off. The floor of the bar area is just wooden slats so that any spills just drop right through.

Weirdly enough, this shitty little room was a highlight for me. This is a crew's quarters all the way at the ass-end of the bar/lounge car. Just off camera is a hilariously tiny closet since there would be pretty much zero downtime other than sleeping or working.

Also they just have a bin of old rail timetables from like 40-50 years ago that nobody wants. You can just grab them. The guide straight up asked us to take some of them off their hands because they take up too much space. Don't mind if I do!
The museum's free and it's not the worst way to kill an hour-ish on a Saturday morning. The area also has some pretty solid lunch options and some good ice cream spots if it's 90+ degrees outside like when I went.

(A chair in the lounge)

(Aforementioned tiny closet on the left)

(Kitchen counter)

(Kitchen proper)

(Radio dials in a family sized sleeper cabin)

(Drinking faucet and pull-out sink in a cabin)

(Non-private sleeper room)

(The newest acquisition which is currently under renovation)
