An engineering and infrastructure firm working on some of Melbourne's biggest transport infrastructure projects - including an upgrade of city loop stations and level crossing removals - has gone into administration putting 3400 jobs under a cloud around the country.

The ASX-listed RCR Tomlinson announced on Thursday it had appointed administrators from McGrathNicol, less than a fortnight after it announced a trading halt on November 12, who immediately signalled they would try to sell the business.

The 120-year-old company employs 3400 people across Australia and lists projects around the country on its website including major solar farms in Queensland, which contributed strongly to the demise of the company, mines in Western Australia and the Auckland city rail link.

In January it was awarded a $70 million contract by Metro Trains to deliver station upgrade works at Parliament, Melbourne Central and Flagstaff stations.

The contract included engineering, design, supply, installation, testing and commissioning of system upgrades for three stations: Parliament, Melbourne Central and Flagstaff stations below the CBD.