the winter of 1951-52, one of the worst ever recorded in the Sierra Nevada. The westbound train "City of San Francisco" got stuck in the 7,000-foot high Donner Pass. 226 passengers and a couple days of nothing to do, and very little food to eat in the dining car

the passengers were stuck on a train with no provisions, for 4 days. I bet those with a deck of cards were popular real fast

For the best account of what happened, and what was necessary to get them out - after a couple wasted efforts, read:
https://www.rgj.com/story/life/2015/01/16/aftermath-stranded-sp-streamliner/21898063/

but keep in mind, without heated cars, the toilet plumbing froze.

On day two, here was the rescue situation, to give you an idea of what a cluster bomb of bad luck they'd gotten stuck in was like:    the rotary plows were working from both directions to reach train No. 101, but an avalanche fell on rotaries 7207 and 7208, killing the engineer. Both the eastward and westward main tracks on Donner Pass were covered by snowdrifts, with four rotary plows either buried in snow or mechanically out of service.

Southern Pacific had made arrangements with the Army HQ in San Francisco for three Army snow "Weasels," as well as doctors, medical supplies, food, fuel for the snow fighting equipment

the equipment was loaded aboard work train Extra No. 6236 East. The plan was to follow rotary No. 7209, plowing the eastbound main on Tuesday. However, the rotary ran out of fuel and water.

SP decided to unload the Weasels and have them try to get through to No. 101 with medical supplies and food. Unfortunately the Weasels could not operate in the soft snow

A relief train was sent with dog sleds, supplies, and a medical doctor. It was to follow a rotary snow plow, but ice on the rail sent the rotary off the tracks west of Soda Springs. 

Like I said, cluster bomb of bad luck

The doctor and supplies continued to the train on a dog sled, assisted by skiers and a Pacific Gas and Electric Company Sno-Cat. A dozen Sierra Club volunteers arrived in two snow-cats laden with 400 pounds of canned food. Four critically ill passengers were evacuated by Sno-Cat.

(Yay Tucker Sno Cat! One of my favorite vehicles... they ought to try and capitalize on this event)

But look through the 41 photos at https://www.sfchronicle.com/thetake/article/Snowbound-in-the-Sierra-3-days-of-hell-on-a-6880330.php#photo-9483387 in a very nice and easy (also no advertising) gallery for the visual of it.

and I bet they ran out of cigarettes too... remember, nearly everyone smoked back then, as cigs were advertised to be so healthy that moms could smoke them around babies.

http://www.trainsandtravel.com/2017/03/11/empire-builder-gets-snowed-in/
https://ctr.trains.com/railroad-reference/operations/2002/01/stranded-streamliner
https://www.tahoedailytribune.com/news/weather-window-a-winter-to-remember-1952-part-2/