To try and improve capacity would it be possible to run the following services off peak
1tph Hereford, Ledbury, Colwall, Great Malvern, Malvern Link, Worcester Foregate Street, Droitwich Spa, Bromsgrove (pickup South/setdown North only) University, New Street
1tph Worcester Foregate Street or Shrub Hill, Droitwich Spa, Bromsgrove, University, New Street
This way Bromsgrove still gets a fast service but less people would board before Bromsgrove as it does not come from Hereford and Worcester would get 2tph fast to Birmingham.
If these trains ran a Half Hourly service Droitwich to Birmingham service then they should fit with the Cross City services as it would follow the same timed service, just half an hour later. Also no XC service runs exactly on the opposite half hour to the Worcester services so should fit with these.
Platform space would not be an issue at New Street as currently off-peak I think services arrive at xx09 and depart at xx50 but a half hourly service would mean a service would arrive at xx09 and depart at xx20 and then again at xx39 waiting until xx50 so noe extra platform space would be needed and this turnaround time is possible as peak hours they wait for this long.
The stock to operate this (until new stock arrives) would be displaced class 170's from the electrified Rugeley line.