They were given the yellow diamond coupling code as they were ordered to work in West Cumberland with the yellow diamond Derby Lightweight sets. However, in the two and a half years before they were delivered plans changed as they were delivered to Walsall while a decision was made on where to use them. They eventually worked in several areas, always in the LMR. These areas included West Cumberland (55997), but were mainly used in the Manchester area based at NH, although on occasions worked south as far as Stafford or Wolverhampton.
At the end of 1958 55998, allocated to Walsall, was noted on regular workings between Walsall, Coventry, Birmingham New Street and Wolverhampton. Working the 8.55am Wolverhampton - Birmingham New St, then 10.25am New Street - Coventry, appearing at Coventry around 10:40, then departing for Birmingham an hour later. This duty had formerly been worked by a Walsall or Monument Lane 2-6-4T with one van. The parcels car then stood in platform 1A at New Street for over an hour before working the 2.25pm New Street - Wolverhampton. Later in the day in worked as required from Alrewas to New. St with produce from market gardens.
At Carlisle, starting with the winter timetable on the 15th September 1958, 55997 began on Carlisle - Whitehaven parcel workings. These had formerly been Upperby 2-6-4T or 2P 4-4-0s, and a Workington Cl2.
The second stage of the Midland area diesel scheme beginning Monday 17th November 1958 saw an additional evening trip to Coventry, returning to New Street at 21:45.
By the end of 1959 55998 was regularly working to Rugby from the Birmingham direction, into the Leamington bay at approximately 11:40, leaving at around 12:30.
During January 1960 55998 was awat at Derby for repair, and steam loco 42659 was a regular stand in with one parcels van, although Royal Scot 46153 was noted on two occassions with the single van!
Pulling tail traffic was not unusual.