Paddy mails, generally considered as being workmen's trains, were operated by, or for many companies to transport their workers to their place of work or between their sites of work. Originally they were operated by railway contractors, on temporary tracks laid to remove spoil from their workings, to transport workers from their "shanty villages" to the work site. Many of these navvies as they were known were of Irish origin, hence the name given to the trains (see: Paddy).