Audio Tube map to guide the blind: Learning the Underground system by sound could make travelling safer. Matthew Brace reports

Imagine travelling on the Tube wearing a thick black blindfold. Imagine not being able to see that vital multi-coloured wall map telling you which trains to catch and when to change lines. Imagine stepping out over a gap between carriage and platform whose width you cannot see nor judge.

Angus McKenzie, a former accoustic engineer from Finchley, doesn't have to use his imagination. Blinded 35 years ago when an eye operation went wrong, he is now helping other blind people to use the Underground safely and successfully by employing their functioning senses.

He has produced a series of audio Tube maps on cassette which will teach the blind to recognise the particular sounds and movement of trains and so navigate their way through the system.

In painstaking detail he has travelled the network, noting all the different clatters and rattles which trains make as they pass through tunnels - all valuable information for blind people.

He said the pitch of track noises can be used to tell which branch of a line the passenger is on, and at certain platforms shared by more than one line - at Moorgate for example - the difference in the sounds of brakes can indicate whether the arriving train is running on the Metropolitan Line or Circle Line.

'You know when you travel from Euston to King's Cross eastbound on the Northern Line there's that odd dip in the track? You might not even notice it but to a blind person that is a very important signal which will tell them where they are and what station is next,' said Mr McKenzie.

His tapes also say which side the train doors open at different stations. 'Once, at Liverpool Street, a train came in and the doors opened on the wrong side. A blind chap stepped out thinking he was going to land on the platform and instead he found himself falling on to the opposite track,' he said.

'Unfortunately there have even been occasional reports of doors opening by accident while the train is still in the tunnel. But these are rare.'

His tapes are also available on computer disc for use with an acoustic keyboard and are being transcribed on to paper in large print for those who are short-sighted rather than totally blind.

Much of Mr McKenzie's inspiration for producing the maps has come from horror stories told by fellow blind passengers, or experiences he himself has witnessed.

'I remember hearing about one man who was trying to get on the District Line and missed his footing because he misjudged the width of the gap and fell between the platform and the station,' he said.

'Then I had a scary moment, just after I got my guide dog, Simon, when I was heading up to Totteridge and Whetstone to take the Northern Line south. The train pulled in and the doors opened. Simon stepped on and I followed, but as I did so the doors closed and trapped my foot outside. I wrenched it open and got my foot inside. I had estimated they had been open for only four seconds - things could have been much worse.'

Mr McKenzie hopes his new tapes will allow the blind to have a safer and more pleasant time negotiating the Underground system, but he knows there are certain unpredictable factors which he cannot change and which will always be baffling to sightless Tube passengers.

'It makes me boil when I hear these bloody buskers everywhere. It's difficult enough when you've lost your sight, but to be deafened as well is terrible.

'You're not allowed to take dogs on escalators because their paws can get stuck in the teeth at the top, so I aim for the stairs. Normally I can hear where the escalators are and avoid them but when people are playing music it is virtually impossible and it makes life very dangerous for us.'

It is the unfamiliar which poses the greatest threat to the blind Tube users: the workmen's hole left half-filled in the ticket hall, the faulty lift door, or the cleaner's bucket discarded at the foot of the stairs.

'We have the same sort of intelligence range as sighted people,' said Mr McKenzie, 'but these simple things fox us and make things very difficult indeed.

'But hopefully with the new audio maps some of the problems at least will be lifted, because blind people should not be deterred from using the Tube.'

(Photograph omitted)