Retail Active, one of Europe's leading mystery shopping companies has been appointed by Network Rail to research more than 500 retailers operating at 15 major stations across the UK.
The aim is to increase the profitability of retailers within Network Rail's stations and to identify ways to drive sales and customer service.
The programme will involve thousands of mystery shoppers, who will visit the locations six times a year - as part of a three year programme.
The retailers include well-known brands such as Marks and Spencer, Sainsbury, Boots, Starbucks, WH Smith, Nero and Bodyshop - as well as a number of small independent operators.
Stations involved include major London terminals Paddington, Victoria, Kings Cross, Liverpool Street, Fenchurch Street as well as Manchester Piccadilly, Liverpool Lime Street and Leeds.
Retail Active's Managing Director, Julian Chamberlain said: "The purpose is to engage with retailers in a spirit of partnership and to monitor and benchmark performance trends and share the results.
"Our regular evaluations and feedback will help Network Rail to develop and maintain good customer service practice with their business partners for years to come.
Laura Pries, Operations Director of Retail Active mystery shopping says: "The main objective is to improve the retail experience for customers - who will have a different set of demands to those on the High Street. Timing and ensuring people get what they need quickly are important. People in a station environment are usually in a rush.
"We have built a questionnaire based very much on the engagement of the secret shopper and how they feel about the experience.
"Some retailers have their own programmes and they wanted mystery shopper research that would work in harmony.
"Network Rail has been very careful to consider its retailers and how they may operate slightly differently to each other.
"Our programme will not penalise retailers because they don't do certain things or if they behave in a slightly different way.
"I believe Retail Active won this contract because we provide arguably the most advanced and meaningful mystery shopping and brand audit research available. We are passionate about what we do, and are a close knit team and provide rich information that makes a huge difference to our clients.
"Network Rail wanted someone who would integrate with them and immerse themselves in their business - and that is what we have done.
Julian Chamberlain added: "We are a fast growing mystery shopping company and our ability to deliver this project with flawless executions means we are the right choice.
"Working with Network Rail enables us to show our true capabilities as the UK's leading Mystery Shopping and Brand Audit company."
