In message , Marratxi
writes

Its hard to believe that there were three stations in what seems quite
a short trip from Blackfriars to Farringdon,

There were actually only two stations, Ludgate Hill and Snow Hill
(renamed Holborn Viaduct Low Level in 1912 and closed in 1916) on the
route you mention. The main Holborn Viaduct station was a terminus on a
short branch off that route.

can anybody point me to a map showing that part of the rail system ?

http://www.londonrailways.net/snowhill.htm

--
Paul Terry