THE compensation bill for work at Queen Street Station could run to tens of millions of pounds.
Network Rail has to pay out to train operators every time a track is closed.
The work is expected to last up to four months with no services able to run into the seven platforms in the country's third busiest station.
Some trains such as Edinburgh services will be diverted to Central Station and others to the low level platforms but not all services will be able to operate.
A separate project closing the Winchburgh Tunnel, near Edinburgh, for 44 days is expected to cost £10million in compensa-tion, the Transport Minister has already said.
The Queen Street tunnel closure will affect more services and be closed for more than double the length of time.
A price has also to be agreed to purchase other land and buildings to allow the redevelopment of the station to go ahead.
Business leaders are concerned the impact the closure will have and the council is awaiting details of the contingency plans for the transport network.
Glasgow Chamber of Commerce chief executive Stuart Patrick said: "The effects of this four-month closure on the business and every-day life of the city will be substantial.
"Glasgow and Edinburgh need the principal rail link in vital areas such as financial services, the Parliament and for tourists spending time in both cities.
"This has come out of the blue, and the question has to be asked, why haven't we heard of it before now?
"We would welcome more detail on why it is happening and on the plans for alternative arrangements."
Gordon Matheson, leader of Glasgow City Council, recognised the necessity of the work to replace the slab track in the tunnel but expected a knock-on effect for citizens business and visitors.
He said: "Queen Street is of pivotal importance to travel in and out of Glasgow and also many journeys within the city itself.
"In that context, this investment is much needed to ensure the station is able to meet the demands of the city.
"However, it is inevitable that major works will bring with them a level of disruption.
"I will be anxious to see what plans operators and the Government put in place to minimise the impact on Glaswegians, businesses and visitors to our city."
Network rail confirmed compensation would be due to ScotRail for loss of access and income, but were unable to put a figure on it at this time.
A spokesman said: "How much compensation is due to each operator depends on how many services are diverted to Central or are routed to the low level and how many are not able to run.
"There will be a cost, but it can't be defined until we know the details of the services affected."
Other transport organisations will have to bear some of the brunt of disruption.
Some ScotRail services are expected to be disrupted, diverted and even cancelled, while work goes on.
SPT which operates the Subway can also expect an impact on access to Buchanan Street during the planned station redevelop-ment and an increase in demand for the service as people look to alternative modes of transport to reach the city centre.
A price has to be negotiated to take ownership of Consort House an eight-storey office block in West George Street and the modern extension to the Millennium Hotel.
SPT bought the building in 2005 for around £18m and the hotel bedrooms are among the most attractive in the city, attracting a premium rate overlooking George Square.
Officials are understood to be seeking full details from Network Rail as soon as possible to allow planning to take place.
A ScotRail spokesman said: "We will work with Network Rail to fully under-stand what the potential impact of any works will be at the station."
With seven platforms out of action during the tunnel work some local services will be suspended for the duration of the closure.
Local services from the north west and north east of Glasgow, through communities including Maryhill and Springburn, could be affected.
LABOUR MSP for Maryhill and Springburn Patricia Ferguson said local commuters making relatively shorter journeys must not be forgotten.
She said: "Everyone understands that vital maintenance work has to take place and that renovation of Queen Street will be necessary but I would hope that disruption to Glasgow commuter services would be kept to a minimum during this work and that the needs of those who travel within Glasgow are recognised."