I am not sure, AmtrakFan, if you have a specific part of the country in mind when you speek of blizzards during the early 1970's. If you are referring to the northwest, I very much remember a couple of winters from 1970-1972.
I was living in the small hamlet of Browning, Montana, a station stop for the (then) Burlington Northern RR and, of course, later Amtrak.
We had one of the coldest winters, during those 2 years, on record. I did take the train west to Seatle a few times, and I can remember all kinds of problems for the train, due to the severe weather. Snowdrifts could be 20 ft high. I have picture of a neighbor's house with snowdrifts above the roof. He had dug out a tunnel into his front door. With the front porch light on, it resembled an igloo. We had temp readings of minus 40 deg for a few weeks..one one or two occasions it got to 50 below. Many of the local ranchers lost cattle due to the cold weather.
Heading west on the train, from Browning, was Glacier Park..only about 15-20 miles from Browning. I can remember going over some of the tressels, looking down at a gorge 400 ft below the track, and feel the wind (sometimes up to 60 mph) swaying the train, back and forth. Not a comfortable feeling.
Richard