Alstom's Ballarat factory will require a new major contract within 12 months to ensure work continues at the site beyond April next year.
Right now, workers in Ballarat are building 30 train cars for five new trains bound for Melbourne's suburban network.
A major contract must be secured in the coming months with a decision on X'Trapolis 2.0 orders still in the balance.
Of the five new trains bound for metropolitan networks, the first six body shells have been delivered to the Creswick Road site from overseas, ready for assembly, which is planned to begin in July.
It's expected they will hit the network by mid-2020.
The workforce is stable at the moment, at least for the completion of the five trains, according to an Alstom spokesperson, but a major contract must be secured in the next months.
While the new X'Trapolis model trains are being built, workers in Ballarat are also modifying existing trains, to bring them up to date with the latest disability standards.
"Going forward this project will run concurrently with the five trains," the spokesperson added.
In October, it was announced the company would design the X'Trapolis 2.0 fleet - the company was not able to comment on this project, referring questions to the state government.
It is understood a decision on the X'Trapolis 2.0 orders will be made at a later date based on the outcomes of the design works.
The state government was committed to increasing local content on the trains and supporting local jobs, a spokesperson said.
"We invested $103.5 million in five new six-carriage X'Trapolis trains in the 2018/19 Victorian Budget to meet growing passenger demand on Melbourne's rail network, while retaining jobs and skills in Ballarat," they said. "We also provided the pathway for a new generation of X'Trapolis trains by investing $10 million in design works, which secured Alstom's Ballarat manufacturing staff through to the start of work on the five new X'Trapolis trains."
The state government has invested more than $4 billion in the last four years for new and upgraded rolling stock, as well as supporting infrastructure, across the entire network.
The X'Trapolis fleet is now at 106 trains, and 19 of the 24 new six-car X'Trapolis trains are now in service.
As reported in October, when the design contract was announced, approximately 65 people are employed at Alstom's Ballarat workshop for X'Trapolis fit-outs and modifications, including four apprentices and trainees.
The new high capacity Metro trains, which will service the new Metro Tunnel, are under construction in Newport, while V/Line VLocity trains are built at Dandenong.