The following is a direct extract from page 184 of Gough, John: "The Midland Railway - A Chronology", 2nd edition, published by The Railway and Canal Historical Society (1989):
"Kirkby Stephen SB: Opened 2.8.1875 // Replacement box: Opened 6.5.1894 // Re-named Kirkby Stephen West SB [no date given] // Replacement box: Opened 27.10.1974"
NB: This structure is the 1974 replacement. For details of the 1875 & 1894 structures, see Structure ID 266480.