23.07.2026
Construction of the Rail Baltica Keila River Bridge in Rapla County began a year before the first machines arrived on site. First, frog barriers had to be installed, experts on bats, fish and otters had to be called in, and a plan had to be drawn up to build the 225-metre bridge with the least possible impact on the Keila River.
This year, work has been underway on the banks of the Keila River in Rapla County, which has involved all the hallmarks of a large infrastructure project: heavy equipment, pollution control booms, sedimentation basins, experts who have reviewed every possible migration route for frogs.
The 225-meter-long railway bridge being cast on site — with five spans, two pairs of rails, and a longest river crossing of 62 meters — is one of the longest railway bridges to come to Estonia during the construction of Rail Baltica, although not the longest: that honor goes to the 320-meter bridge over the Pärnu River.
According to the builders, the Keila River Bridge is technically ordinary; what is extraordinary is how much effort has been put into ensuring that train passengers won't notice anything extraordinary when they look out the window in a few years.
Because the construction has turned out to be much more than just an engineering challenge - it took almost a year to prepare for the start of the work, and solutions ranging from amphibian barriers to hay bales acting as natural filters had to be implemented to protect the Keila River and floodplain.
The bridge is being built by Järelpinge Inseneribüroo in collaboration with Verston. According to its director Aivar-Oskar Saar, the Keila River Bridge has little mystery: a cast-in-place, towed box bridge with variable height, the working design of which the office has only slightly optimized compared to the main design. “In terms of design, it is a conventional modern structure,” Saar admits, giving the closest comparison from Tallinn: the Peterburi Road viaduct crossing the Tartu highway.
According to the engineer, the structure is not rare in the world, but the soil around the Keila River made the construction difficult. “The most demanding construction is probably the construction of the trusses and pillars that remain in the ground of the bridge, which we were forced to establish with the river, karst area and weak soils using sinkholes.”
Nature conservation set the pace of construction
While the engineers were challenged by the difficult soil conditions, the greatest challenge for the builders was the sensitive natural environment of the Keila River.
Verston Project Manager Andre Mägi says that one of the most complex areas of the entire Rail Baltica project was the Keila River crossing: “The Keila River bridge construction area was one of the most complex areas of the entire project precisely because of the environmental protection requirements.”
Before the work began, experts on amphibians, bats, fish and otters were involved, and some of the preparatory work had to be done a year before construction began. For example, amphibian barriers were installed in the fall of 2024 so that work could begin the next construction season when conservation restrictions allowed.
The environmental work does not end even after the bridge is completed.
“After the main construction work, we will also carry out restoration work, the aim of which is to restore the amphibian habitats affected during construction and ensure their future functioning,” describes Mägi.
Hay bales proved to be an effective natural filter
One of the most difficult tasks was cleaning the surface water accumulated during construction before releasing it into the environment.
To this end, a solution consisting of several sedimentation basins and a water drainage system was built to prevent suspended solids from reaching the Keila River. In addition, during the heavy equipment works, pollution control booms were installed along the river in case of oil or fuel pollution. However, they did not have to be used during construction.
However, the most unusual solution was hay bales.
“As an interesting solution, we also used hay bales during the filling work in the Keila River embankment. They acted as a natural filter, helping to capture fine particles and reduce the amount of suspended solids reaching the Keila River. What seemed like a simple solution turned out to be very effective in practice.”
The builders also built a temporary pedestrian suspension bridge across the Keila River during the work, which will allow the work crew to quickly move between both banks of the river and make the construction process smoother.
According to Mägi, the Keila River Bridge is a good example of how engineering solutions and nature conservation must be combined when building modern infrastructure, because building skills alone are not enough to achieve a successful result - just as important were thorough preparation, careful scheduling of work, and close cooperation with various nature experts throughout the project. This way, construction activities can take place in a way that ensures both the smooth running of the work and the protection of the Keila River and the surrounding natural environment.
The active construction of the bridge is estimated to last one and a half years, and an average of twenty people, mainly from Harju and Rapla counties, are working on the site - a small but not insignificant example of how a project costing billions reaches local households and the local accommodation sector.
When traffic on the Rail Baltica route opens, passengers will rush across it in a matter of seconds and only manage to notice the river and bridge out of the corner of their eye.
The article was first published in Õhtuleht's content marketing section on July 16, 2026.
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