There were actually plans for nuclear powered locomotives in the 1950'ies. E.g. the X-12 by Lyle Borst. See e.g. https://books.google.co.uk/books?id=bVMEAAAAMBA

There were actually plans for nuclear powered locomotives in the 1950'ies. E.g. the X-12 by Lyle Borst. See e.g. https://books.google.co.uk/books?id=bVMEAAAAMBAJ&lpg=PA78&ots=oNcGmhCvuD&dq=x-12+locomotive&pg=PA78&redir_esc=y&hl=en#v=onepage&q=x-12%20locomotive&f=false https://books.google.co.uk/books?id=bVMEAAAAMBAJ&lpg=PA78&ot...