Zagreb
20 February 2026 – HŽ Infrastruktura has launched a public procurement procedure today for technical assistance services related to the Integrated Project Delivery (IPP)/Alliance contract model for the construction of the long-planned lowland railway between Zagreb and Rijeka.
The tender does not concern construction works themselves. Instead, it covers consultancy services to support the preparation and implementation of a future procurement procedure for works, the drafting of contract documentation, and advisory support during the design and construction phases.
The deadline for submission of bids is 31 March 2026, with the value of the procurement set at €1.5 million.
First use of Alliance model in Croatia
The IPP, or Alliance contract, is a modern approach to delivering large and complex infrastructure projects.
It is based on a partnership model between the contracting authority and contractors, aimed at fostering collaboration rather than transferring risk.
This marks the first time such a model will be used in the Republic of Croatia. The lowland railway project will therefore represent a milestone in the national infrastructure system.
Unlike traditional contracting models, where risks are often shifted onto contractors, the Alliance model requires all key participants to:
• Operate as a single, integrated team
• Jointly manage risks
• Ensure full financial transparency
• Resolve disputes within the project framework, avoiding court proceedings except in exceptional cases
Additional features of the model include:
• An open-book principle, ensuring complete cost transparency
• Unanimous decision-making on key issues
• A focus on achieving the best outcome for the project as a whole, rather than protecting individual interests
The Alliance model has been successfully implemented on major infrastructure projects in countries such as Estonia, Finland, the United Kingdom and New Zealand, particularly where projects involve high technical complexity and uncertainty.
Strategic European corridors
The lowland railway forms part of three significant Trans-European Transport Network (TEN-T) corridors: the Mediterranean Corridor, the Baltic Sea–Adriatic Sea Corridor, and the Western Balkans–Eastern Mediterranean Corridor.
These corridors connect the Port of Rijeka with Hungary and other Central European countries, strengthening Croatia’s role as a key logistics and transport hub.
The new double-track railway will be electrified and designed for speeds of up to 160 km/h. Plans include the construction of five new stations and one additional stop.
Given the demanding terrain along the route, extensive engineering works are required, including 17 viaducts and 14 tunnels.
Once completed, the line will significantly increase rail safety and capacity. It will also allow trains up to 750 metres in length to operate, enhancing freight potential and supporting further development of the Rijeka port basin.
This includes the possibility of expanding port facilities to the island of Krk, in Omišalj, positioning Rijeka as a leading port in the northern Adriatic.
The sections Karlovac–Skradnik and Skradnik–Krasica–Tijani are currently in the conceptual design phase and in the process of obtaining location permits. These are expected to be secured by the end of 2026.
Once completed, the lowland railway from Zagreb to Rijeka will span approximately 175 kilometres, reducing the current route by 56 kilometres.
The estimated value of the entire project stands at around €3 billion. A more precise cost assessment and construction timeline will be defined following the completion of conceptual designs and a market price analysis at the time of launching the construction tender.
In 2025, the Karlovac–Tijani sections received environmental approval, with the Ministry of Environmental Protection and Green Transition issuing a decision confirming the project’s acceptability from an environmental standpoint.
The launch of the technical assistance tender marks a significant step forward in one of Croatia’s most important infrastructure projects.