Passenger complaints at London Midland fell by 73.3% when compared to the same period last year.
The latest data released by the Office for Rail Regulation (ORR) compare the Q3 results for 2013-14 compared against those recorded in 2012-13 and show a reduction from 148.9 complaints per 100,000 passenger journeys to 39.7.
London Midland recorded the biggest fall in complaints out of all 19 UK-based train operating companies.
Richard Brooks, of London Midland, said: “We have worked extremely hard to improve performance and reliability, as we know these are the two factors that drive customer satisfaction.
“The results demonstrate that we have turned a corner following the difficulties we faced in 2012, and I’m delighted that our customers are feeling that.”