I’d look at creating a high frequency all-electric system, with 3 all-stations routes, all operating at 2tph.
Leeds to Huddersfield via Bradford
Huddersfield to Leeds via Dewsbury
Leeds to Brighouse via Bradford
Leeds to Brighouse via Dewsbury
All of the services would form others, and some stations (Low Moor, Bramley, Cottingley, Morley, Batley, Ravensthorpe and Deighton) would get no services other than these. The other locations would keep the Calder valley/TransPennine services, thus giving them a new/faster service to Manchester and Leeds, as well as other destinations less frequently.
At Leeds, it’d need 1 platform for Bradford trains only and 1 platform for Dewsbury trains only.
You’d also need 2 in total at Huddersfield, as turnarounds would be 18 minutes with my calculations of journey times.
Diagram 1 (8 units needed): LDS - BDI - HUD - DEW - LDS - DEW - HUD - BDI - LDS
Diagram 2 (6 units needed): LDS - BDI - DEW - LDS - DEW - BDI - LDS