Dated as being the 21st . May of 1958 this view would well be prior to 10201 's transfer from Camden to Willesden which took place in the late 'fifties and has the former Southern Region's prototype on an express passenger working at or about the time when problems were being experienced with the train heating equipment , consequently relegating the three in the class to freight duties during the Autumn and Winter months , and frequent and lengthy periods being stored out of use , mainly at Derby .br/ Built at Ashford in late November of 1950 an evaluation period at Derby had taken 10201 to the Derby Technical Centre in January of 1951 from where the locomotive worked the Manchester to St . Pancras route but the demanding gradients on that Midland Region route proved too much for a locomotive designed for the relatively easy Southern Region main lines , and 10201 was returned back home to Ashford after just four weeks at Derby .br/ 10201 and her sister 10202 were both transferred to Camden in April of 1955 , to be followed by 10203 in the following July , their duties on the Southern Region having ended during the mid ' fifties.