I am now running 2 B sets rescued from 3 wrecks, thanks to your advice. The original carriage was knocked off my garden shed layout by the cat about 20 years ago, sustaining a cracked roof and broken end. I have replaced the couplings with the new Hornby (Dapol) type. Now the two carriages only need some repairs to the underframe, vents buffers and some replacement Bachmann wheels as has been suggested. Thanks again.