Budapest-Belgrade Railway Line Reopening Delayed
The much anticipated reopening of the Budapest-Belgrade railway line and the relaunch of a direct train service have been delayed due to major technical issues affecting the project.
Budapest to Belgrade railway line
Since the main railway line between Budapest and Belgrade was closed for upgrade works in 2019, the direct train connection between the two capitals has been suspended.
With the railway line in Serbia already modernised and works on the Hungarian section between Budapest and the border at Kelebia now completed, hopes were high that direct Budapest-Belgrade train services could start in March 2026.
However, according to Hungarian media, it could be many months before a direct train connection between Budapest and Belgrade resumes.
Although the first freight trains have already run on the renovated Budapest-Kelebia line, which has been double-tracked and upgraded for speeds of up to 160 kilometres per hour (100 mph), major technical problems are currently preventing the operation of passenger trains.
Technical issues
The technical issues affecting the new Budapest-Belgrade railway line involve the signalling and control system.
According to Hungarian media reports, the signalling and train control systems, built to the European ETCS standard, are not yet operational and have not received the required authorisation.
Without a fully functioning ETCS, only one train can run in each direction on the entire 160-kilometre-long (100 mile) railway line from Budapest Ferencváros to Kelebia, with the next train only cleared to depart once the first has completed its journey to the Serbian border.
Moreover, without ETCS in place, trains can run at a maximum of 100 kilometres per hour (62 mph) or just 40 kph (25 mph) in mist or poor visibility.
Needless to say, this has major consequences for overall capacity on the railway line, which is designed not only for passenger traffic but also for freight, the primary reason for its reconstruction.
Authorisation
The reason the signalling and train control systems have not yet been approved is that they were reportedly built by a Chinese company completely unfamiliar with European requirements.
Initially, the plan was to install the same domestic Chinese signalling and train control system that has been implemented on the Serbian section of the line.
Although this Chinese system is advanced, it is not configured according to EU requirements and was therefore not an option in Hungary.
Reportedly, the company overlooked and underestimated how time-consuming it is to set up an operational ETCS signalling and control system on the Hungarian section of the line, which is causing the current delay.
Rolling stock issues
Although the control system on the Budapest-Belgrade railway line could be operational in as little as two weeks, it may take much longer for direct trains to start due to other issues.
First of all, the compliance review of the railway line, which will take at least two months, has not yet begun.
There is also the issue that trains and locomotives must be equipped with on-board ETCS to operate on this line, and while many other railway lines have alternative systems as a backup, the newly renovated Budapest-Belgrade line is equipped exclusively with ETCS.
At present, MÁV, the Hungarian Railways, does not have enough ETCS-equipped electric multiple unit (EMU) trainsets and locomotives to operate both elsewhere in the country and on the new Belgrade line for passenger and freight services.
This could also cause problems if the overhead lines fail or electricity is otherwise cut, as MÁV does not have a single shunting or diesel locomotive with on-board ETCS that could operate on the line to rescue a stranded train.
Moreover, the technical compatibility between the ETCS systems in Hungary and the Chinese systems in Serbia is not yet fully clarified.
As the Serbian signalling and control systems were built to Chinese specifications, experts do not know whether a locomotive equipped with on-board ETCS will be able to operate in Serbia, or whether trains such as the Serbian Soko high-speed train can run across the border in Hungary.
Furthermore, the operation of ETCS requires a telecommunications system, GSM-R, which has not been installed on the Serbian side, meaning that SIM cards in Hungarian locomotives cannot roam there, and this is reportedly also an issue for Serbian trains in Hungary.
Locomotive change
All the problems affecting the Budapest-Belgrade line could mean that train services may only start with a time-consuming locomotive swap at the Hungarian-Serbian border.
This would inevitably increase the journey time and disrupt the originally planned timetable, which was intended to reintroduce not only direct Budapest-Belgrade trains but also through Vienna-Budapest-Belgrade services.
As bad as the news is for passenger services, it may be even worse for freight, given the extra locomotives required and the resulting increase in costs.
Direct passenger trains will eventually run again between Budapest and Belgrade, but exactly when this will happen, and what the services will look like, remains uncertain.
Conclusion
The reintroduction of direct trains between Budapest and Belgrade, initially set for March 2026, will be postponed due to numerous issues with the signalling and control system.
According to local media, the Hungarian section of the line does not yet have a fully functioning ETCS, the EU-standardised automatic train protection system, and once completed, a compliance review will take at least two months.
Moreover, the technical compatibility between the ETCS systems in Hungary and the Chinese-built system in Serbia is not yet fully clarified.
It remains uncertain whether Serbian trains will be able to operate in Hungary, or Hungarian trains in Serbia, with a time-consuming locomotive change at the border still an option.
