Contractors worked around the clock to install a new traffic bridge, which is part of the £33m Wakefield Eastern Relief Road project.
The 5.5km by-pass on the east side of the city will provide links from Aberford Road to Doncaster Road.
It is being built by Wakefield Council and is part of plans to build 2,500 homes in a development project called City Fields.
The council said the link road would reduce traffic congestion by providing an alternative route avoiding the city centre and will give direct access to the M62.
It will cross the Kirkgate to Normanton railway line and the River Calder on new bridges and it is expected to be open in Spring 2017.
Contractors worked from 11pm on Christmas Eve to 8am on Sunday, 27 December to install a 1,200 tonne traffic bridge underneath the railway lines serving Wakefield Kirkgate Station, near to the Eastmoor estate.
Council leader Coun Peter Box, who is also the West Yorkshire Combined Authority chairman, said: “Manoeuvring the new bridge into place while there were no trains for two days over Christmas was a critical element of progressing the eastern relief road. Had the works not been completed by the 8am deadline it would have meant major disruption to the local railway network and a substantial increase in the scheme’s costs.
“I am delighted the operation was a success despite the very wet conditions.
“This was an excellent piece of coordination and planning and I would like to congratulate everyone involved on the operation’s success.”
Coun David Dagger, the council’s cabinet member for transport and highways, said: “I am very proud this major engineering feat has been successfully completed.
“It was a huge challenge and it marks an important landmark in this major project.”
The railway lines serving Wakefield Kirkgate Station were cut and removed to allow the contractors to excavate a hole in the existing embankment.
The bridge, which had been constructed over several previous weeks was then carried into position using specialist low-loading platform trucks.
Parts of the excavated embankments were then refilled and the railway lines re-laid in time for the railways to open on Sunday, December 27.
The Wakefield Eastern Relief Road is the first project to be paid for from a £1bn transport fund made available by the government.
Infrastructure projects are being funded as part of the Leeds City Region Local Enterprise Partnership (LEP) Growth Deal.