British Rail Class 206
The British Rail Class 206 or 3R was a type of diesel-electric multiple unit (DEMU) first created in 1964. They were re-formed from Class 201 and Class 416 vehicles for use on Reading-Redhill-Tonbridge (North Downs Line) services. Six three-car sets were created, numbered 1201–1206.  They were nicknamed 'Tadpole' units because of the contrast between the wide-bodied 416 'head' and the narrow-bodied 206 'tail'.