The document sets out the findings and recommendations resulting from a 20-month programme of work assessing the benefits, impact and likely timescales and cost of completing the remaining 4.6km of tramline 1A.
Councillors will be asked to back the next stage of the project despite substantial problems with the first section that saw costs double to £776m and main contractor Bilfinger Berger taking years longer to complete than anticipated.
A report accompanying the OBC will be considered at a special meeting of the council’s transport and environment committee on 4th September, before going to full council on 21st September 2017.
The report seeks authority to begin procurement to identify a potential contractor for the project, with a final decision on whether to go ahead with taking the tram to Newhaven, and with which contractor, to follow in autumn 2018.
The business case says that for every £1 spent, the economic return to the city would be £1.64. Capital cost is estimated at £165.2m, including risk and inflation.
It says that construction would take three years, including 18 months on Leith Walk, followed by approximately four months of testing and commissioning on the new line. A significant proportion of major utility works have already been carried out, while the remainder could be carried out in conjunction with main infrastructure works, meaning no ‘double digging’.
It also says that lessons have been learned from last year’s official inquiry into the project.
Council leader Adam McVey said: “Edinburgh is growing faster than any other city in Scotland and our current road network and public transport provision simply aren’t sustainable given the number of new residents we’re expecting to welcome here over the next two decades.
“Rather than exacerbating traffic problems on our already congested roads, trams allow far greater numbers of people to travel, while creating employment during construction, boosting development along the route and connecting people to centres of employment, leisure and retail.”
Transport convener Lesley Macinnes added: “Given the experience of the last tram project, we’re acutely aware of the need to scrutinise this business case as rigorously as we possibly can – residents deserve nothing less. We won’t take any decision on completing the line to Newhaven until we are 100% confident that the project can be delivered, financed and managed effectively.
“Councillors from all parties have been taking up the opportunity to fully examine the business case over the past weeks and will use this special meeting of the transport and environment committee to quiz officers further on the detail and make a recommendation on whether to progress to the next stage.”