The Y1/Y3 sentinel was based on the road going lorry, utilising a similar centrally mounted steam tube boiler and chain drive system to the wheels. Whilst not having the greatest turn of speed (approximately 36mph top speed) these small locos proved capable of pulling a constant draw weight and were considered ideal for shunting in yards and providing motive power along smaller branch lines.
These quirky little locos were used by all of the big four railway companies but it was the LNER that used and ordered greatest number. Many Y1’s and Y3’s were produced and continued to provide service until their phased withdrawal over the 1940’s and 1950’s. Seven survived into departmental stock until the 1960’s. only two Y1/Y3’s survived into preservation in the UK.