As far as I know the only Tenshodo Big Boys with stamps on the back of the cabs were the runs in '57 and '58.
Hello, I am resident in Washington State and aquired an old Tenshodo 4884 Big Boy. my question to you from basic information is this...my engine appears to have a three digit number stamped on outside back panel of the cab. 1.01, the dot is positioned at the top not as it is typed here. If this is the serial number can you share with me what you know this to be as far as the engines age? Thank you.