 Under British Railways , classes D1 , E1 , H , N1 , M7 , Q , Q1 , Std 3 2 @-@ 6 @-@ 2T , Std 4 2 @-@ 6 @-@ 0 Std 4 2 @-@ 6 @-@ 4T and U1 were permitted to work between Tonbridge and Grove junction . Freight trains from Tonbridge West Yard were not permitted to depart until the line was clear as far as Southborough Viaduct . Other classes of locomotive known to have worked over this section of line include C , and E4 . 
