In addition to the different available lengths, the buses are sold with a variety of prime movers, ranging from conventional diesel, LNG/CNG combustion engines, diesel-electric hybrid and hydrogen fuel cell with a traction motor.

The Axess was the first full-size heavy-duty transit bus, defined as ENC building both the chassis and body, offered by the company.

Previously, ENC had built medium-duty mid-size transit and shuttle buses, with the company building a custom body on a commercial chassis.

With 738 kWh of energy storage, the Axess EVO-BE delivers a longer range per charge, making it ideal for transit and shuttle applications.

Axess EVO-FC offers an estimated range of over 400 miles with its high-power hydrogen fuel cell and proven electric powertrain.

[27] SunLine received eight additional AFCBs with the same drivetrain as FC3 and improvements to the battery and fuel cell cooling systems[28]: 4–5  between 2014 and 2018, which were assigned fleet numbers FC4 through FC12 (skipping FC7).

[30] Unlike FC3, which had its powertrain and fuel cell installed in New York, the subsequent AFCBs were all assembled entirely at ElDorado National's Riverside, California factory.

[28] By July 2018, ENC had produced 20 fuel cell buses for transit agencies throughout California,[31] including SunLine, UC Irvine (2015),[32] and OCTA (2016).