The most recent range of Graham Farish small diesel locomotives are excellent on dcc. The new chassis type with enclosed can motor is capable of producing genuine shunting speeds in n gauge. Converting these to dcc is both affordable and very worthwhile
Please have a look at the link below
https://www.wicknessmodels.co.uk/wickness-information/specific-manufacturers-on-dcc/graham-farish-locomotives/graham-farish-small-diesels