Some of our readers mentioned this scary 1972 Christopher Lee film in the comment section and I've found a good copy for viewing in tonight's Chiller Theater.
Horror Express, also known as Pánico en el Transiberiano (Panic on the Trans-Siberian Express), is a 1972 Spanish/British horror film directed by Eugenio Martín and starring Christopher Lee, Peter Cushing, Alberto de Mendoza and Telly Savalas. It was produced by Bernard Gordon and written by Arnaud d'Usseau and Julian Zimet (credited as Julian Halevy). The film is based on the 1938 novella "Who Goes There?" by John W. Campbell.
Campbell's novella was also the influence for Howard Hawks' and John Carpenter's "The Thing," movies.