InnoTrans 2022 (25)

At InnoTrans 2022 Stadler Rail has presented a large variety of units. At the forefront of its display were models with alternative propulsion, the first of which was the FLIRT H2 with hydrogen fuel cells. In the USA, alternative propulsion units are referred to as ZEMU (Zero Emission Multiple Unit). The train pictured here, 3501, is the first member of an order for two ZEMUs ordered by the San Bernardino County California Transit Authority (SBCTA) from Stadler US in November 2019 for the so-called Redlands Passenger Rail Project. This is a 14.5 km stretch between the San Bernardino Transit Center and the University of Redlands in the eastern suburbs of Los Angeles, where Arrow services are operated by FLIRT DMUs from 24 October 2022.

The hydrogen-powered trains are essentially identical to the DMUs, except for the propulsion of course. The FLIRT H2 identically has two passenger cars, but in the middle is an 8 m long Power Module that houses the hydrogen technology (fuel cells, H₂ tanks and cooling). This location also complies with US legislation requiring complete separation of the pressure vessels from the passenger compartments.

Six FCmove- HD+ (Fuell Cell, Heavy-Duty) fuel cells each with a 100 kW power are used on FLIRT H2. They were produced by Ballard Power Systems of Canada as of 2021 and are designed for 25,000 operating hours. The Hydrogen Storage System (HSS) is rated at 350 bar (35 MPa) and it takes approximately 30 minutes to refill providing a range of approximately 460 km. Traction batteries of the lithium titanate (LTO) type with capacity not yet specified are placed on the roof of both cars.

The FLIRT H2 has a Bo' 2' 2' Bo' axle arrangement, the traction power including battery power is 700 kW (i. e. the same as the FLIRT DMUs), however, during regenerative braking it can reach a braking power of up to 1,450 kW. The maximum speed is 79 mph (127 km/h). The train offers 120 seats and, like the aforementioned SBCTA DMUs, has several differences compared to European FLIRTs due to the US operation conditions. These include a different type of speedometer, a warning bell (in addition to the horn) and a domestic PTC (Positive Train Control) ATP.

In general, rolling stock for the US tends to be more robust than trains for Europe, which on this hydrogen FLIRT means more massive front crash zones. But it is also worth noting, for example, the driver's seats, which are of Spartan design compared to European solutions: this can be seen not only in the way they are fixed into the floor, but also in the bulk metal seat frame, the armrests fitted on steel tubes and the design of the padding. A similar impression can also be obtained in the interior, where it is perhaps most evident on the tables.

SBCTA states that the FLIRT H2 is the first hydrogen train project in the USA, and the main motivation behind is the desire to introduce low-emission operation on non-electrified lines, of which United States has the vast majority. It is one of 28 California transformation projects selected for funding under the Transit and Intercity Rail Capital Program, which is administered by The California Department of Transportation Caltrans and The California State Transportation Agency CalSTA; in this case, support for hydrogen trains is 30 million USD. All of these entities are listed on the Power Module, along with the name of the Metrolink transit system.

On the Redlands Passenger Rail Project line, there is a roughly half-hourly interval of Arrow services during the peak hours and an hourly interval off-peak. According to a study conducted in a California context, while hydrogen is more expensive compared to BEMUs (which is also true elsewhere), it offers the advantage of not requiring intensive power supply to recharge the batteries during short turnarounds compared to battery units, as hydrogen propulsion has a full day's stock of fuel. On the Redlands route, the FLIRT H2 is expected to travel 500 km daily without refuelling, even in very hot weather and therefore with high air conditioning output.

The first vehicle is expected to be transported to the USA in early summer 2023, while tests are underway in Europe in the meantime. Type approval and entry into service with passengers is expected in 2024. In addition, a memorandum of understanding was signed at InnoTrans, where Caltrans and CalSTA are asking for 4 four-car hydrogen FLIRTs, with an option for 25 more.