Actually, I think Mom was on the MS Stockholm on her first trip in 1955. In 1956 she took the MS Kungsholm. Here's an old postcard I found on the web. It hit the Andrea Doria a year later with loss of life of five crew members on the Stockholm, and 40 altogether on the Andrea Doria. Here's a picture of the damage to the Stockholm.
Photo from http://www.ssmaritime.com/Stockholm.htm or click here. It has lots of info on the liner and the collison.