COMSA Corporación specialises in the construction and maintenance of railway infrastructure and superstructure—including conventional railways, high-speed lines, tramways, and metropolitan and regional networks—as well as in the engineering, installation and maintenance of overhead contact lines and traction substations for both alternating and direct current systems.
The company develops, designs, installs and maintains railway safety, signalling and communications systems, in addition to solutions for network management and control centres.
Its activities also include the manufacture and supply of ballast; the production of concrete sleepers for mainline tracks and turnouts; the execution of civil engineering works and building projects; and the delivery of engineering and project management services. 
Furthermore, COMSA Corporación is active in the field of comprehensive railway vehicle maintenance and in the rental of high technology machinery.

Top products: INFRASTRUCTURE: 1. Construction of the Bergara Junction, the convergence point of the three high speed branches to Bilbao, San Sebastián and Vitoria. 2. Design and construction of the Yellow and Green lines of the Lisbon Metro. TRACK: 3. Renovation and automation of Madrid Metro Line 6. ROLLING STOCK AND TRACTION EQUIPMENT: 4. Adaptation and modernisation of PMA31m car carrier wagons for Pecovasa.

Spain:
With 135 years of history, COMSA Corporación is a specialist in railway projects covering construction, installations and systems, and maintenance for high speed lines, tramways, and metropolitan and regional railways.

High speed rail
COMSA is involved in flagship projects such as the remodelling and enlargement of the concourse at Chamartín station in Madrid, which includes the construction of four new tracks for high speed services; the construction of La Sagrera station in Barcelona; and works on Sector 3 of the Mondragón–Elorrio–Bergara branch of the Basque Y network. It has also taken part in strategic actions within the Mediterranean Corridor, such as the implementation of the third track between Martorell and Sant Vicenç de Calders.

Conventional lines
The company is delivering key projects including the construction of the new railway access to Terminal 1 of Barcelona–El Prat Airport, the undergrounding of the R2 commuter line as it passes through the urban centre of Montcada i Reixac, the southern rail bypass of Bilbao, and the extension of the A Pobra de San Xiao bypass in Lugo.

Metros and tramways
COMSA continues to consolidate its role as a benchmark company in the construction and modernisation of metro and tram systems. Following the commissioning of the Barcelona Tram connection along Avinguda Diagonal and the extension of Line M1 of the Palma de Mallorca metro, the company is progressing on strategic projects such as the development of the Altza–Galtzaraborda section of the Donostialdea Metro; the construction of the Galdakao–Hospital section of Line 5 of Metro Bilbao; and the central section of Line 9 of the Barcelona Metro. Among its most significant projects is the renewal and automation of Line 6 of the Madrid Metro, a strategic contract that will make L6 the first fully automated line in the network.
In parallel, the group maintains a substantial volume of contracts for upgrading and maintaining infrastructure, electrical installations and systems in the main metro networks in the country—Madrid, Barcelona, Valencia, Seville and Malaga—reinforcing its presence in the urban transport sector and its contribution to the continuous improvement of sustainable mobility in cities.

Electrification
COMSA Industrial complements the group’s railway infrastructure activity through its specialisation in electrification, systems installations and telecommunications. Notable projects in this area include the construction of the overhead line and contact wire installations for the Basque Y network; the electrification of the Altza–Galtzaraborda section of the Donostialdea Metro; the electrification of the new railway access to Terminal 1 of Barcelona Airport; and the electrification of the tracks north of Valladolid Campogrande station, among others.
The company also carries out the maintenance of overhead contact lines, substations, stations and associated systems for FGV in Alicante.

Europe:
Backed by its highly specialised railway expertise and more than a century of experience, COMSA Corporación focuses on markets with strong opportunities for the development of new infrastructure and the modernisation of existing networks. In this regard, it has strengthened its presence in Portugal, where COMSA and its subsidiary FERGRUPO are delivering the expansion of the Yellow and Green lines of the Lisbon Metro, as well as the excavation and support works for the Ramales tunnel section, part of the future Circular Line of the Porto Metro.
In addition, the company has completed the renewal of the Pampilhosa–Santa Comba Dão section of the Beira Alta line and is progressing with the rehabilitation of the track superstructure on the Vouga Line, among other projects.

Americas:
In Mexico, over the past financial year, COMSA carried out the track and systems rehabilitation project for Line 1 of the Mexico City Metro, and it is currently engaged in the renewal of the Zaragoza workshops. The company is also advancing the modernisation of the Tasqueña terminal of the Light Rail and performing comprehensive maintenance of Lines A and 12 of the Mexico City Metro.
In Colombia, it is delivering the maintenance, conservation and improvement works on the La Dorada–Chiriguaná railway corridor.

COMSA Corporación is involved in various innovation projects linked to the railway sector. Its participation as a member of the European Smart Green Rail (eSGR) consortium in 4 of the 6 projects of Europe’s Rail Joint Undertaking (ERJU)—R2DATO, IAM4RAIL, Rail4EARTH and FutuRe—is particularly noteworthy. All of these initiatives aim to accelerate the development and deployment of innovative solutions for the European railway network.

Other notable initiatives include MARTINI, which focuses on developing algorithms for the predictive maintenance of railway tunnels through the use of computer vision and structural analysis.

The group also promotes its own innovative solutions, such as NEOBALLAST®, a new railway ballast technology that incorporates recycled materials and enhances infrastructure performance by reducing vibrations, maintenance needs and environmental impact.

As a company specialised in the development of railway infrastructure, COMSA Corporación is a member of the Board of In-Move by Railgrup and is also part of the Spanish Railway Technology Platform (PTFE), which is integrated into the European Rail Research Advisory Council (ERRAC). In addition, COMSA Corporación is a founding partner and board member of The Railway Innovation Hub Spain, and it participates in organisations that promote the implementation of BIM methodology, such as the Interministerial BIM Commission of the Government of Spain and BuildingSmart.

Railway Operations
Following the award of the Railway Undertaking Licence and the Single Safety Certificate by the Spanish State Railway Safety Agency, COMSA has begun operating as a Railway Undertaking for the transport of its own machinery.

Quality
ISO 9001 certification, covering all areas in which the company operates, including the maintenance of high speed track and turnouts.

Sustainability and Environmental Management
The first company to receive the Construction Companies Sustainability Contribution Index certificate, a unique recognition evaluating sustainability from a 360º ESG perspective, encompassing performance, social, economic and environmental indicators.
The company also undertakes projects certified under LEED (Leadership in Energy and Environmental Design) and BREEAM (Building Research Establishment Environmental Assessment Method).
The group is listed in the international Carbon Disclosure Project (CDP1) registry and in the Carbon Footprint, Offset and CO₂ Absorption Projects Register of MITECO, having achieved the “Reduzco” level in 2023 and the “Compenso” level in 2024.
Additionally, in 2025, COMSA and COMSA Industrial achieved certification of their Water Footprint, ISO 14046, a recognition that quantifies the potential environmental impacts related to water—both from its consumptive and degradative use—throughout their activities and processes.

ISO 14001 certification: issued with full scope across all company activities.
ISO 50001 certification for energy management.
ISO 14064 certification for greenhouse gas quantification across all activities in Spain.

R&D and Innovation
The R&D&I Management System is certified under the new ISO 56001 standard, in line with the regulatory transition prior to UNE 166002 being phased out in July 2026.

Information Security and Digitalisation
COMSA Industrial has obtained ISO 27001 certification and ENS (Spanish National Security Scheme) certification in information security (Medium category), both issued by AENOR.
ISO 19650 1/2 certification for the organisation and digitalisation of information in building and civil engineering works using BIM, achieved in March 2022. Notably, COMSA Corporación is a pioneer in BIM implementation, with a dedicated department established more than 10 years ago.

Occupational Health and Safety
ISO 45001 certification for the occupational health and safety management system, issued with full scope across all company activities.