The new standard-gauge line consists of a project to upgrade the existing 970km narrow-gauge railway from Dar es Salaam to Isaka and construction of a new 494km extension to Kigali and a 197km branch from Keza in northwest Tanzania to Musongati in Burundi. The line will be built primarily for freight trains with a 32.4 tonne axleload proposed although some passenger services will be available.

A 2014 study of the DIIKM project by Canarail and Gibb Africa updated a previous 2009 study by DB International and BNSF and emphasised optimising alignments to reduce capital expenditure. It also projected potential traffic for the line, with the line expected to carry 10 million tonnes per annum (mta) by 2020, 13mta by 2030, and 19mta by 2050.

The governments have yet to decide on a preferred PPP structure for the estimated $US 5-6bn project and are encouraging bidders to state their preference and reasons why in their submissions. The deadline for expressions of interest to the Rwanda Transport Development Agency is August 14 at 11.00.

Tanzania's transport minister Mr Samuel Sitta said in June that a contract for a new line from Dar es Salaam to Isaka had been awarded to a Chinese consortium led by China Railway Materials. However, it is unclear whether this project has now been scrapped in favour of the PPP project.