I travelled from Harrow On the Hill station on Southbound Met Line train on Wednesday 14th May around 8am. The train was packed at this peak time but to our disbelief three sets of doors were defective and did not open. The train was allowed to run till we got to Wembley Park station – when they decided to take it out of service. This posed a serious safety and means of escape issue causing chaos and congestion. No explanation was given to the commuters for this occurrence. Can you please explain how common this occurrence is and why the faulty train was not terminated at Harrow On The Hill and allowed to run for a further 3 three stations. Was the problem associated with age of the stock and can you assure that this is not a common problem with Met Line and rest of the other underground trains?