Simplify the following text for a Grade 8 native English-speaking person.
Original: The British Rail Class 02 were a class of twenty 0-4-0 diesel-hydraulic shunting locomotives built by the Yorkshire Engine Company in 1960 ( first ten , D2850-D2859 ) and 1961 ( D2860-D2869 ) for service in areas of restricted loading gauge and curvature such as docks .
Simplified: The British Rail Class 02 were a class of twenty 0-4-0 diesel-hydraulic shunting locomotives . They were built by the Yorkshire Engine Company in 1960 ( first ten , D2850-D2859 ) and 1961 ( D2860-D2869 ) .