Thanks, Ollie!
From First Great Western JourneyCheck:
Line problem: between Great Malvern and Hereford.
Owing to a problem with line-side equipment between Great Malvern and Hereford all lines are blocked. Train services through these stations may be subject to disruption on all routes at short notice. An estimate for the resumption of normal services will be provided as soon as the problem has been fully assessed.