Transports Montreux-Vevey-Riviera has awarded Stadler a contract to supply two custom-built electro-diesel Abt rack locomotives for engineering trains on the 11 km, 800 mm gauge mountain railway between Montreux and Rochers-de-Naye.

The four-axle HGem 4/4 locomotives will measure 13.5 m long and 2 234 mm wide, with a maximum speed of 25 km/h, a maximum power output of 1 320 kW and starting tractive effort of 220 kN. Those figures matter on a line whose Abt rack section climbs from Montreux to Rochers-de-Naye at 2 042 m above sea level; the locomotives are specified to haul maintenance and infrastructure trains on gradients that conventional adhesion stock cannot serve.

Stadler said the design places an emphasis on ergonomics and a functional workplace, with large front and side windows to give the crew good visibility — a practical consideration for drivers working engineering trains on a mountain line.

Bussnang build, 2029 entry into service

The locomotives will be built at Stadler's Bussnang factory and enter service in 2029. That timing matches the delivery of eight three-car panoramic electric multiple-units that MVR ordered from Stadler in May 2025, aligning the renewal of both passenger and maintenance fleets within a single window.

Stadler also holds a separate contract to equip the line with its Nova Pro communications-based train control system, adding signalling to a portfolio that now spans rolling stock and infrastructure technology on the route.

'With these two new locomotives, we are reaching an important milestone in the comprehensive modernisation of our Rochers-de-Naye line,' MVR Managing Director Yves Marclay said on October 1. 'Not only are we renewing our passenger trains, but at the same time we are laying the foundations for reliable and efficient infrastructure maintenance. Together with the new signalling technology and the renewal of the railway infrastructure, this creates an integrated system that will equip us for the coming decades.'

Frédéric Evequoz, Head of Sales for the Tailormade product segment at Stadler, described the line as 'an exceptional project' that 'beautifully illustrates how we develop rolling stock and signalling technology to meet the specific requirements of a railway'.

Electrification upgrade alongside fleet renewal

The locomotive order forms part of a wider investment programme by MVR in the line's infrastructure. The operator is renewing the overhead electrification and converting the supply from 850 V DC to 1.5 kV DC, a change that increases the power available through the overhead line and supports the operation of the new locomotive and EMU fleets.

Taken together, the programme covers four fronts: eight new panoramic EMUs ordered in May 2025, the two HGem 4/4 engineering locomotives announced this month, the Nova Pro CBTC roll-out, and the 1.5 kV DC electrification conversion. MVR is treating these as one integrated system rather than separate projects, with all elements due to converge by the end of the decade.

The 220 kN starting tractive effort of the new locomotives indicates their intended role: heavy infrastructure work on steep rack gradients, where reliable low-speed pulling power determines whether maintenance trains can operate at all. For an operator renewing track, electrification and signalling simultaneously, having purpose-built engineering locomotives delivered on the 2029 timeline reduces the risk of a maintenance bottleneck once the new passenger fleet and CBTC system are in operation.