The regional manager of First Great Western has accepted an invitation to join commuters on a much-criticised rail route.
Andrew Griffiths was asked by Northavon Liberal Democrat MP Steve Webb to travel with him from Yate to Bristol.
Mr Webb said people were being failed by the Swindon-based rail operator, which was warned last month to improve or lose its franchise.
The firm was criticised for delays, cancellations and over-crowded trains.
Mr Webb said he wanted Mr Griffiths to hear first hand passengers' frustrations about the poor quality of service that they receive.
The train was due to get in at 0836 BST, but arrived six minutes late.
Mr Griffiths said he had spoken to several passengers en route to Bristol and did not know why the train was late.
"Our performance hasn't been good enough," he said.
"At the end of last year we were positioned bottom of class, in April we have improved.
"We are running nine out of ten trains on time, six minutes late is classed as not on time, which is a bit disappointing."