Automatic rig for bypass between tunnels

This technology ensures the automation and safety of the tunnel lining segments during the creation of the bypasses.

The rig therefore allows the bypass to be made while the main tunnels are being excavated, with a significant reduction in costs.






(scenario A)


(scenario D)



composed of hydraulic pistons, centrings and spars


with telescopic uprights


for vehicle passage

patented system.svg




The system with centrings enters the tunnel
STEP 2.1
Centrings open and adhere to tunnel walls
STEP 2.2
Centrings open and adhere to tunnel walls
STEP 2.3
Centrings open and adhere to tunnel walls
Assembly operation ends, platform lowers and wagon disconnects
Wagon exits and leaves the passage free
Wagon with new centrings goes through the structure for next bypass


Whatis it for?

This technology guarantees the safety of the tunnel cladding panels during the creation of the bypass tunnel between tunnels. The concrete-reinforcing system therefore makes it possible to create the bypass tunnel while excavating the main tunnels.

What are the benefits?

Using this technology allows to consistently reduce the costs, thanks to the drastic reduction of the time necessary to complete the works, of the number of people involved on site, and to the possibility of rapidly re-using the centrings for a subsequent bypass tunnel.

With this working method it is not necessary to frequently interrupt the passage of vehicles in the tunnels, as it otherwise can happen for weeks or even entire months; in this case instead, the passage is blocked only for those few hours necessary for transport and to proceed with the concrete-reinforcing operations.

The automation of the process on one side ensures a significant reduction of the risk factor of falls and injuries of staff people, since they do not have to manually install the metal support structures of the cladding panels (which are several meters above the ground); on the other side, the lower number of transport vehicles makes the risk of possible accidents at work drop.

It should be underlined that this technology makes it possible for construction vehicles to circulate during the excavation of the main tunnel and of the bypass. Moreover, if a second bypass becomes necessary, the system's shape allows the passage through the previously installed structure, making it faster to carry on the work.

In which kind of tunnels is it possible to apply this technology?

It is possible to apply this technology to every vehicular and rail tunnel.

How does the wagon work?

The wagon works thanks to a remote-controlled and servo-assisted technology.
Two diesel engines (whose power can vary according to worksite needs) produce the about 400 kilowatts required for the system to work. On demand, it is possible to make the whole system explosion-proof.

What services do you provide?

Vexa takes care of providing the technology, the assistance or the managing of the operations until the complete executions of all works.

What does the price depend on?

The price depends on the specific needs of the customer and on the own characteristics of the tunnel, considering:

  1. sections of the main tunnel and of the bypass
  2. ground reaction impulses
  3. dimensions of the cladding panels
  4. number of bypass openings simultaneously active 

When the customer requires it, it is possible to unbundle the price elements related to:

  1. centrings (one for each access point to bypass)
  2. carrying-centrings wagon
  3. vehicles passage platform.

It is also possible to rent the system with a long-term chartering contract, finding together the most suitable solution for the payment instalments.


Our company has the requirements to offer the following services: