Staff analyzed the feasibility of using current battery electric and hydrogen fuel cell zero emission (ZE) locomotive technologies from the Port of Los Angeles (POLA) to Barstow, a high-traffic freight route in California. For a train to complete a trip from POLA to Barstow, there must be sufficient power and energy supplied from the locomotives throughout the trip. To determine the number of current ZE locomotives required to pull 283 containers on 130 railcars from POLA to Barstow, power and energy required to complete the trip needed to be calculated while taking into account length of trip, track grade, rolling resistance, and drag. Once the power and energy required to complete the trip were calculated, staff were able to determine the minimum number of ZE locomotives required to supply the power and energy needed. The ZE locomotive models being evaluated in this analysis are Wabtec’s FLXdrive Heavy-Haul battery electric locomotive, Progress Rail’s SD70J-BB and SD70J battery electric locomotives, and Canadian Pacific Kansas City's (CPKC) hydrogen fuel cell locomotive with a tender car to carry hydrogen fuel. These models were chosen as they are rated for line haul operation and could be used by Class I railroads.

Analysis Assumptions

Route from Port of LA to Barstow

The route from POLA to Barstow is approximately 174 miles with elevation as low as 17 feet and as high as 3,800 feet above sea level. The analysis splits the route into five segments as shown in Figure 1. The five segments were defined based on significant differences in elevation change. For example, Segment 1 has no elevation change, while Segments 2 and 3 have elevation changes with hill grades of 0.6% and 2.2%, respectively. Segments 4 and 5 are downhill portions of the route.

Power and Energy Requirements

The power and energy required to travel along each segment of the route from POLA to Barstow were calculated. Power was calculated by finding the net force required for the locomotives to pull the train multiplied by the train’s velocity. The net forces calculated along each segment considers the force to overcome a hill against gravity, drag force, and rolling resistance (frictional forces).  Energy requirement was calculated by multiplying power by the time it takes to travel along that segment based on the train’s velocity.

The mass of the 283 containers and 130 railcars was calculated using the methodology found in the San Pedro Bay Ports Emission Inventory Methodology Report (https://kentico.portoflosangeles.org/getmedia/2f6e4e7c-6197-493b-bf3e-e3b7ea26b6eb/SPBP_Emissions_Inventory_Methodology_v4). The total mass of the train is equal to the sum of the railcar mass with cargo and locomotive mass. To determine the number of ZE locomotives required to complete a trip from POLA to Barstow, a minimum energy and power requirement was determined. Staff found that Segments 1-3 require the use of energy from the locomotive, while Segments 4-5 do not. Therefore, the minimum energy required to complete the trip is the sum of the energy needed in Segments 1‑3. A minimum power requirement was determined by determining the most power required by a segment. Segment 2 has the largest power requirement due to its steep grade and speed of travel, so the Segment 2 power requirement was set as the minimum power requirement for the train to complete the trip from POLA to Barstow. Depending on the speed, Segment 3 could require more power than Segment 2.

Analysis Results

The table below shows the minimum number of ZE locomotives required to complete the trip from POLA to Barstow for different locomotive types and models. The analysis also compares the number of locomotives required for different factor of safety (FOS) values to account for errors (up to 20%) in power and energy calculations.

Key Takeaways

The limiting factor that impacts the number of locomotives required to travel from POLA to Barstow is energy capacity. Due to the inclines along Segments 2 and 3, a locomotive with more energy capacity is favorable. The analysis concludes that for a train consisting of 130 railcars and 283 containers, between four to nine line haul battery electric locomotives (depending on model and FOS) are required and four hydrogen fuel cell locomotives with one hydrogen tender and battery augmentation are required to complete the trip from POLA to Barstow.

Staff estimates that the analysis result is scalable to heavier or lighter trains. That is, a 50% increase in the number of railcars and containers will result in up to 50% more locomotives required for all four ZE models (when FOS is 1 and not including combinations of different types of locomotives within a train). While the relationship between train mass and number of locomotives needed is not exactly linear, the trend generally holds. The weight of railcars and containers contributes most to the power and energy required to complete the trip, thus affecting the number of locomotives needed.

Discontinuous Overhead Catenary Systems

While the route from the POLA to Barstow can be done by just battery electric locomotives alone, there are benefits to utilizing overhead catenary systems (OCS) compatible locomotives with battery electric locomotives in the same train. By using discontinuous OCS, the OCS-compatible locomotives pull the train in electrified segments and the battery electric locomotives pull the train in non-electrified segments. The use of OCS along certain segments of the route from the POLA to Barstow can significantly reduce the number of locomotives required to complete the trip because the energy demand needed from battery electric locomotives would be less than if the trip were done by battery electric locomotives alone.

In addition to the energy and power advantages, when a train consisting of OCS-compatible and battery electric locomotives is under an OCS segment, the battery electric locomotives can recharge using pantographs connected to the OCS lines. This would help increase the operational range of the battery electric locomotives.

The table below highlights the number of locomotives needed based on how OCS infrastructure is implemented along the route from the POLA to Barstow.

Please see the Feasibility Analysis: Zero Emission Train from the Port of Los Angeles to Barstow document below for more details about the methodology and results.