To be honest, with the expansion of EV's over the coming years, I doubt the B5TLs will be on the X21 beyond 2024/2025 (8 year old), most likely end up on the 58 by then.

The B5TLs should suffice until at least then and are ok for now.

However whilst I doubt new vehicles will be purchased for the X21 (diesel or electric), given the following route profile:

- Constituencies = Build back greener = Support from Government
- Infrastructure at Consett depot
- Routes serving Redheugh Bridge, Bensham Bank, Tyne Bridge and Central Station

I could potentially see something like the X30's/X70's getting EV's BUT not until at least 2024-25ish. That would then allow 6341-49 to succeed 6308-14 & 6334-35 on the X21 with 6350/51 providing enough Euro 6 spares or being split across GNE along with 6338-40 to provide backups should GNE choose ADL/BYD for their EV decker orders.