The plans to upgrade London Bridge have been prompted by the need for additional lines as part of the Thameslink 2000 project.
The predicted increase in passenger numbers when the Jubilee Line Extension opens has also encouraged Railtrack to look at the retail prospects for the station.
Project sources said the designs could include provision for a large amount of retail space, and proposals being considered range from a “lick of paint to a mini Broadgate-style development”.
Robin Lovell, Railtrack development control and planning manager, confirmed that the company was looking at upgrading the station.
“The Thameslink proposals would involve significant work at London Bridge Station and we are looking to see what we could involve at the same time,” he said.
The architect, which is working with engineer Alan Baxter Associates, has six to eight weeks to complete the study before presenting its designs to Railtrack. QS on the project is Cyril Sweett.
It is thought that designs will be submitted to Southwark Borough Council in June.