The resignalling work is part of a $US 65m track-doubling project on a 16km stretch of the line in the Pančevo area, which includes construction of a second electrified track, upgrading of the existing track and stations, and a new bridge over the Tamiš river.
The line currently carries around 60 trains per day, although traffic is expected to increase to around 136 trains per day by 2020.
Alstom will supply its Smartlock 400 computer-based interlocking for the project, which is due to be completed in 2016. Alstom's share of the deal is worth around $US 13m.
The project is part of a broader programme of investment in the Serbian rail network, which is being financed with the aid of a loan from Russia.