Hamburg’s underground network is expanding

The U4 Horner Geest project is expanding Hamburg’s underground network with two new stations and a 2.5-kilometre extension, improving connections for residents in the east of the city while construction continues alongside active metro operations. The project relies on openBIM and a cloud-based Common Data Environment, enabling close collaboration between Hamburger Hochbahn and OBERMEYER and allowing all disciplines to work with a shared 3D digital model. In the article, Dagmar Kilian, BIM Manager at Hamburger Hochbahn, and Markus Hochmuth, Managing Director of OBERMEYER Digital Solution, share their insights on how BIM, digital data and collaborative workflows are transforming the planning and delivery of complex infrastructure projects.

Read the full article below in English, and find the link to the original German version.

Hamburg’s underground network is expanding – thanks to openBIM and cloud collaboration

THE NEW STATIONS OF THE HAMBURGER HOCHBAHN

Next stop: the mobility transition

East Hamburg is set to gain two new underground stations. To this end, the U4 underground line will be extended by two stations and 2.5 kilometres, and once completed, this will represent a giant step towards the mobility transition for nearly 13,000 people. Soon, the journey from Horner Geest to Hamburg Central Station will take just 13 minutes. The construction project is called “U4 Horner Geest” and is challenging in many respects, as rail operations must continue unhindered during the works. For this major infrastructure project by Hamburger Hochbahn, the company has therefore brought an experienced partner on board – and relied on cloud collaboration and openBIM from the outset.

The first passengers in 2026

An existing station is being extended with an additional platform, a new single-track tunnel is being built, and two further stations are being added – a project placing high demands on everyone involved in the construction plan. Construction has been underway since February 2021, with the first passengers expected to board by the end of 2026. The project, on which many trades are working, is regarded as a “model district for the mobility transition”. Hamburger Hochbahn therefore decided to use openBIM, a method based on the open exchange of models – regardless of the software used.

Dagmar Kilian, BIM Manager at Hamburger Hochbahn AG, was able to convince her employer to adopt openBIM and is delighted with the successful pilot project, which was planned by the lead designer OBERMEYER Infrastruktur GmbH & Co KG and advised by OBERMEYER Digital Solution. The consultancy firm is driving forward the digital transformation within the holding company and for external clients: “OBERMEYER Digital Solution made our project possible in the first place with their BIM expertise. I personally take great pleasure in this trusting collaboration.

“Technologically, the transition to BIM is no longer a challenge. The task is rather to support people on their journey towards BIM.”

—Dipl.-Ing. Markus Hochmuth,, Managing Director of OBERMEYER Digital Solution GmbH

Complex construction, simple communication

Extending a metro line brings with it many challenges. Inner-city construction is complicated in itself, as work must be carried out around existing infrastructure. In the case of Hamburg, buildings were also demolished, and during the construction phase, surprises can repeatedly arise in the building fabric, some of which is 100 years old. Meanwhile, rail operations must, of course, continue. “Most trades converge at an underground station. Clear communication and coordination are essential – and this is easiest to achieve digitally,” explains Markus Hochmuth. The use of openBIM enables collaborative working and ensures product harmonisation.

OBERMEYER and Hamburger Hochbahn are also relying on collaboration within a Common Data Environment (CDE) for the project. This allows all parties involved to work on a single model, securely stored in the cloud. With the model constantly updated, there are fewer misunderstandings, there is no need to send huge new files back and forth, and outdated data is a thing of the past. This speeds up the planning process and promotes error-free data exchange. Overall, design and project complexity is better managed – drastically reducing errors and rework.

Digital data as a “treasure”

Markus Hochmuth, Managing Director of OBERMEYER Digital Solution, highlights another advantage of the BIM method: “The overall 3D model makes the work much more transparent. In the past, to trace a previous step, I had to trawl through folders and hope that the work had been done properly back then. Today, I can do it with just a few clicks. This digital data in the project is simply a treasure.” Of course, work must be structured from the outset. However, there are suitable processes in place to rule out misunderstandings.

According to Hochmuth, controlling and quality assurance also benefit. With the help of the data obtained, the digital way of working can help companies determine: Where are we efficient? Where are new business areas that we can tap into? What should we focus on? Which processes can be automated and standardised? For the U4 Horner Geest project, ISO 19650 has already been implemented – the international standard for managing information throughout the entire lifecycle of a structure – using Building Information Modelling (BIM).

“I’m designing a bridge for the tenth time and there are recurring steps that are merely a means to an end. I want to automate and standardise these. That way, I can concentrate on my engineering work.”

—Dipl.-Ing. Markus Hochmuth, Managing Director of OBERMEYER Digital Solution GmbH

A working environment for young professionals

Dagmar Kilian recognises the power of modern working structures: “We are committed to continuously developing Hamburger Hochbahn. And that includes digital tools. This is another reason why Hamburger Hochbahn is a popular employer among young professionals starting their careers.” Markus Hochmuth confirms this: “Given the current market situation, it would be very difficult for us to attract staff if we didn’t take a methodical approach and rely on digital processes.”

Hamburger Hochbahn AG

Hamburger Hochbahn AG is the largest transport company in Hamburg and was founded in 1911. It is wholly owned by the City of Hamburg and operates both the Hamburg underground and the majority of the city’s bus network. In 2019, the company carried approximately 462 million passengers. Over 6,000 people work for Hamburger Hochbahn AG, including just under 130 apprentices and around 1,000 employees in the technical department.

OBERMEYER Digital Solution GmbH

The internationally active engineering firm OBERMEYER is a general planner with a correspondingly broad portfolio, covering both building construction and infrastructure planning, and offers its services through several independent companies. OBERMEYER Digital Solution GmbH was founded in 2021 following the split of the former OBERMEYER Planen + Beraten GmbH into two companies: OBERMEYER Infrastruktur GmbH & Co. KG and OBERMEYER Gebäudeplanung GmbH & Co. KG. The brand was founded in 1958 and has since enjoyed a reputation as an excellent construction planner. Today, the group has holdings both domestically and abroad, employing more than 1,200 staff. Dipl.-Ing. Markus Hochmuth: “Years ago, we devised a BIM strategy for the entire group and developed standards. Through our work, we support the digital transformation of OBERMEYER and external clients.” His company is also a certified training provider in accordance with VDI/bS-MT 2552, Sheet 8.1.