The Quebec City-Windsor corridor (the Corridor) is the busiest and most important trade and transportation corridor in Canada. The transportation sector is the second largest greenhouse gas (GHG) emission category in the country. This paper develops estimates of the potential for CO2 emission reductions in the freight transportation sector by estimating demand for premium-intermodal services between the main Corridor destinations. CO2 reductions are estimated on the basis of a stated-preference carrier-choice survey of shippers in the Corridor. Survey data were used to develop mode share models for five different categories of shipments between eighteen city-pairs. A railyard-catchment approach was taken to arrive at estimates of contestable intercity truck traffic using a subset of the Ontario Ministry of Transportations Commercial Vehicle Survey. CO2 emissions were based on current truck traffic estimates, and emissions factors obtained from MOBILE6.2C. The results show that premium-intermodal service has the potential to capture a significant share of traffic between the main Corridor destinations with potential CO2 emissions reductions in the range of 0.058 to 0.484 Mt a year.