Proterra Catalyst BE35

**Power/Fuel** | Electricity

The **Proterra Catalyst** is the company's second generation battery electric low floor transit bus. First launched as a 40-foot bus, the 35-foot Catalyst BE35 was announced in October 2015. Dallas Area Rapid Transit, who has purchased seven buses, was the launch customer. The pilot bus was unveiled at the 2017 American Public Transportation Association Expo and delivered to DART at the start of 2018.

The Catalyst uses a monocoque structure composed of E-glass fibre stitched non-crimp fabric and unidirectional carbon fibre in a vinyl ester resin. It is moulded using the Seeman Composites Resin Infusion Molding Process (SCRIMP), a vacuum-assisted closed infusion molding method, by TPI Composites. A gel-coat layer is first placed in the mould followed by triaxl glass fibre fabic. Unidirectional carbon fibre fabric is used to add strength at key areas. Quadriaxial quasi-isotropic glass fibre fabric is used where strength and stiffness are especially critical. The materials are vacuum bagged and infused with catalyzed vinyl ester resin. The resulting compsoite structure is lightweight and can absorb a large amount of energy in a collision.

The upper body from the roof down to the lower window line, which includes the entire windshield and rear window, is on section. The lower body from the lower window line to the floor is another. The upper section of the roof and the ceiling are glass fibre sandwich structures with a balsa wood core. Components such as doors and interior fittings are attached by either molding stainless steel inserts into the laminate or by bonding.

In a standard fast charge (FC) configuration, the bus can travel up to 55 miles before the lithium–titanate batteries need to be recharged. An extended range (XR) battery option allows the bus to travel up to 235 miles between charges. At the 2016 American Public Transit Association (APTA) Annual Meeting, Proterra unveiled their E2 (Efficient Energy) battery option with a capacity of 440 to 660 kWh that allows the bus to travel up to 251 miles. This range is able to meet a full day's worth of service for some agencies.

At the 2017 American Public Transit Association EXPO in Atlanta, Proterra introduced their DuoPower drivetrain. It integrates two 190 kWh electric motors and two-speed transmission into a planetary axle from AxleTech. It boasts almost twice the horsepower as the standard ProDrive drivetrain and is five times more efficient than a standard diesel bus. With the DuoPower drivetrain, the 35-foot Catalyst E2 has a nominal range of 302 miles.

The bus's batteries can be charged enroute with a proprietary overhead charging station, which features automatic docking. The standard FC option can be fully charged in ten minutes, while the XR option can be fully charged in approximately one hour. The bus can also be plugged in using a J1772 CCS charger at the garage. The E2 is only charged this way while the bus is out of service, typically when it is parked overnight, at the garage and is fully charged in three to four hours.

The 35-foot Catalyst has a slightly different appearance from the 40-foot Catalyst. The headlights have been re-positioned and the windshield has been reshaped. The tail lights are round rather than rectangular.

## Operators

### United States

* Asheville Redefines Transit - Asheville, NC
* Breckenridge Free Ride - Breckenridge, CO
* Citibus - Lubbock, TX
* Charlotte Douglas International Airport Shuttle Service - Charlotte, NC
* Delaware Area Regional Transit (DART First State) - DE
* Dallas Area Rapid Transit (DART) - Dallas, TX
* Duarte Transit - Duarte, CA
* Florida State University - Tallahassee, FL
* Los Angeles Department of Transportation (LADOT) - Los Angeles, CA
* Missoula Urban Transportation District - Missoula, MT
* My Ride Rock Hill - Rock Hill, SC
* Ride-On - Montgomery County, MD
* South Metro Area Regional Transit - Wilsonville, OR
* Topeka Metropolitan Transit Authority - Topeka, KS **(on order)**

## Demonstrator and engineering units

Below is a list of known demonstrator and engineering buses.

* Demo with SMART August 21, 2021

## References

1. ↑ Proterra Expands its Catalyst™ EV Bus Platform to Include a Nimbler Bus. Press release. 05 October 2015. Protera, Inc. Retrieved on 16 November 2016.
2. ↑ DART Demos New Proterra Zero-Emission, All-Electric Buses. 10 January 2018.
3. ↑ 3.0 3.1 Dawson, Donna. [https://www.compositesworld.com/articles/a-clean-technology-for-clean-zero-emissions-buses "A clean technology for clean, zero-emissions buses." CompositesWorld, 01 October 2018.
4. ↑ Proterra Catalyst® E2 Series Sets New Industry Precedent with a Nominal Range of up to 350 Miles. Press release. 12 September 2016. Protera, Inc. Retrieved on 16 November 2016.
5. ↑ Proterra Introduces the DuoPower™ Drivetrain for its Catalyst® Zero-Emission Buses at APTA. Press release. 09 October 2017. Proterra.
6. ↑ Proterra, bus maker, aims to follow Tesla model. Retrieved on 02 September 2014.
7. ↑ Proterra Introduces Extended-Range Electric Bus, Flexible Battery System. Press release. 24 February 2016. Protera, Inc. Retrieved on 16 November 2016.