I found this here on RTT http://www.realtimetrains.co.uk/train/U63322/2014/08/26/advanced and wondered if anyone knows what it actually is. This would be very helpful
Interesting route. Via Derby Way and Works, and thence via Lichfield
According to this, http://www.prclt.co.uk/2014-Duchess-whereabouts.pdf , 46233 will based at Crewe HC from 24th July to be used on charters during the whole of August and September. So I assume it's already at Crewe.