HWH shed has EMD locos, and while alco required for trains like Padatik is catered by BWN and rarely UDL also comes into scene.
HWH div being near till date caters link very well to SDAH division and when almost all circulating route is electrified, and ply suburban and non suburban EMUs, I guess there's no need of having a dedicated shed for diesel locos, rarely you find trains of D-loco, it's just a very small percentage of all originating trains take in account of HWH or SDAH div alike.