This might be the closest you can get to Frodsham Junction:
http://maps.google.co.uk/maps?ll=53.307096,-2.700748&spn=0.004564,0.01929&gl=uk&t=m&z=16&layer=c&cbll=53.307094,-2.700743&panoid=ufyoWClzm_sXHY7pCBnlWA&cbp=11,90.01,,0,0
There's also Chester Road on the opposite side of the viaduct...