When the Peterbrough - Grimsby Town service ended on Monday 5 October 1970 due to the withdrawn of passenger services from the Spalding - Grimsby Town section, it left a Peterborough - Spalding service.
In the Great Britain Passenger Timetable it was included in Table 19 (0.5 mb pdf).
The crew change ends at Spalding, they will depart with the 13:05 service to Peterborough, 23 July 1977. So what has happened around the destination blind on E56448? My guess is that it was leaking and an attempt was made to seal it with a water based sealant, which was then out in the rain at speed before it had properly set. See also https://www.transporttreasury.com/p1022126417/eb18cb0d4. Robert Thomas.
Cravens Class 105 2-car dmu 56139/51261 has just arrived at Spalding on the 17.35 from Peterborough on 20 July 1981. After a short wait it will return as the 18.07 to Peterborough. Lewis Bevan.
Spalding on 21 July 1981 - E51261 + E56139 have arrived on 17.35 ex-Peterborough and will now form the 18.07 back to Peterborough. Lewis Bevan.
A couple of Cravens 105 twin car units move out of the bay at Spalding to form a working to Peterborough in April 1982. Stephen Burdett.
Norwich allocated Class 105 DMU set 32 formed of E50371 + E56419 departs from Spalding with the 12:53 to Peterborough on 8 May 1982. Stuart Mackay Collection.
Class 101 Metro-Cammell 2-car Norwich set 88 so presumably 54060 + 53208 (DTSL+DMBS) departing Peterborough for Spalding, 12-6-91ish. On Tour With The Class 13 Army.
Audley End-Bartlow
Boston-Lincoln
Cambridge-Ely
Cambridge-Ipswich
Cambridge-Mildenhall
Cambridge-St Ives
Camden Road-North Woolwich
Cleethorpes-Barton-on-Humber
Cleethorpes-New Holland Pier
Colne and Stour Valley Lines
Colchester/Wivenhoe - Brightlingsea
Doncaster-Cleethorpes
Ely-March-Peterborough
Firsby-Skegness
Grantham-Boston
Grantham-Lincoln
Grantham-Nottingham
Grantham-Skegness
Hatfield - Dunstable
Harwich-Manningtree
Hertford North-Huntingdon
Ipswich-Felixstowe
Ipswich-Lowestoft
Kings Lynn-Hunstanton
Lea Valley Lines
Lincoln-Cleethorpes
Lincoln-Sheffield
London-Hertford North
London-Welwyn Garden City
Long Melford - Bury St Edmunds
Lowestoft-Yarmouth
North Walsham - Mundesley-on-Sea
Norwich/Cromer- Melton Constable
Norwich-Ely
Norwich-Kings Lynn via Dereham
Norwich-Lowestoft
Norwich-Sheringham
Norwich-Wells via Dereham
Norwich-Yarmouth
Peterborough-Cambridge
Peterborough-Grimsby Town
Peterborough-Spalding
Romford-Upminster
Royston-Cambridge
Saxmundham-Aldeburgh
Sheffield-Barnsley
Sheffield-Cleethorpes
Sheffield-Doncaster-Hull
Sheffield-New Mills
St. Margaret's-Buntingford
Sudbury-Colchester
Thetford-Swaffham
Upminster-Tilbury
Wickford-Southminster
Willoughby-Mablethrope
Witham-Braintree
Witham-Maldon
More lines will be added in the future!