Railway Credit Union - Mandan Share: Credit Unions Railway Credit Union - Mandan Visit Website Request Info 1006 E Main Street Mandan, ND 58554 (701) 667-9500 (701) 667-9600 (fax) About Map About Full service credit union with offices in Bismarck and Mandan. What's Nearby? Distance: 5 10 15 20 25 50 mi.