Pantograph Charging for Electric Buses: What Transit Agencies Need to Know

Pantograph charging is one of the biggest decisions a transit agency makes when it electrifies a bus fleet. It affects depot layout, capital budgets, labor, and how fast buses get back into service. It also comes with tradeoffs that are easy to miss until construction is finished.

We sat down with Phil Exley, Sr. Director Strategy & Partnerships at Camber Charging, to break down how pantographs work, when they make sense, and where projects go wrong. Phil supports pantograph projects across North America, including Camber’s contract to deliver 73 on-route chargers at more than 20 LA Metro sites ahead of the 2028 Olympic and Paralympic Games.¹ Here is what agencies should know.

Key takeaways

• Pantograph charging is automated and hands-free. A contact head lowers onto rails on the bus roof, so no one handles a cable.
• North American agencies mostly use inverted (pantograph down) systems because they keep weight and moving parts off the bus.
• Every fleet needs depot charging. En route charging is a top-up that only pays off on consistent routes with predictable layovers.
• A pantograph costs roughly two to three times more per connector than a plug-in dispenser, in Camber’s experience. Agencies buy back that premium in time and labor.
• Full deployment takes about 16 months to more than 4 years. Utility coordination is the step that cannot be compressed.
• Most failures happen at the interfaces: vehicle alignment, charger-to-bus communication, and rushed commissioning.

What is pantograph charging and how does it work?

Pantograph charging is an automated way to deliver high-power DC charging to an electric bus through a contact head that connects to rails on the vehicle’s roof. The technology was adapted from rail, and SAE International standardized the connection types for buses in its J3105 recommended practice in 2020.²

The charger typically hangs from a fixed structure, such as a canopy, a gantry inside a garage, or a mast that resembles a highway light pole. Phil describes the mechanism as “a dinosaur claw on a two-rail system.” A session works in four steps:

1. The driver pulls the bus into the charging position.
2. The bus and charger connect wirelessly to confirm the bus is in place.
3. The pantograph lowers and makes contact with the roof rails.
4. The charging session starts, with no cable for the operator to handle.

The weak point is alignment. If the bus stops outside the charging envelope, the session aborts and the driver has to back out and try again. “You’d be surprised how many failed pantograph sessions come down to misalignment,” Phil says. “There’s some play, but you’re often talking inches, not feet.”

What is the difference between pantograph down and pantograph up?

The difference is where the moving mechanism lives: on the charging structure (pantograph down) or on the bus (pantograph up). SAE J3105 defines both as standard connection types.²

North American agencies have largely chosen inverted systems, and Phil points to two reasons. First, weight: “Agencies want to carry as many passengers as possible within gross vehicle weight limits, and the battery is already heavy.” Second, durability: keeping a mechanism off the roof avoids constant vibration from city driving. Cost points the same way, since a pantograph up design puts a mechanism on every bus instead of one at each charging position.

Should you use depot charging or en route charging?

Every electric bus fleet needs depot charging; en route charging (also called opportunity charging) is a top-up that only makes sense when specific route conditions are met. “Depot charging is your foundation,” Phil says. “If you can size your depot with enough power to avoid en route charging, your capital and operating costs will be lower.”

Phil looks for four signals that an agency may need en route chargers:

• Range gaps: block lengths exceed the bus’s usable range.
• Short overnight windows: too little time to charge the whole fleet at the depot.
• Depot constraints: limited space, or limited hostler labor to plug in every bus.
• Power access: the utility can deliver power to a terminal or layover point without years of delay.

The route also has to be consistent, with layovers that are predictable and long enough, and the charging site must be secure. Many agencies end up with a mix of both.

How long does en route charging take?

A typical en route pantograph session lasts 7 to 10 minutes, which fits within the operator breaks most agencies already schedule. In Camber’s experience, a bus gains roughly 1% state of charge per minute, so a 7 to 10 minute stop adds about 7% to 10%, or 20 to 30 miles of range. Camber’s LA Metro deployment uses 360 kW on-route systems paired with pantographs for exactly this use case.¹

Is pantograph charging more expensive than plug-in charging?

Yes. In Camber’s experience, a pantograph costs roughly two to three times more per connector than a plug-in depot dispenser, and agencies justify the premium through faster charging and lower labor.

Connector cost only. Excludes power cabinets, structures, civil, and electrical work.

Phil frames it as a time-versus-money decision. “How much time do you have to dwell at the depot, and how fast do you need buses back on the street?” Some agencies run buses 20 to 21 hours a day with only about 3 hours of overnight downtime. In those cases, he says, a pantograph is often the only option that can push enough power into large batteries in time.

How long does it take to deploy pantograph charging?

A pantograph project typically takes 16 months to more than 4 years from first planning conversation to buses in service, based on Camber’s field experience.

Agencies that applied for the FTA’s Low-No program have often finished much of phase 1, since that program requires a fleet transition plan. Phil’s top piece of advice: “Start the utility conversation before anything else. That’s the one step you cannot compress.”

What are the most common problems with pantograph charging?

Most pantograph problems happen at the interfaces between the bus, the charger, and the site. “Projects go wrong at the handoffs,” Phil says. Four issues come up most often.

1. Vehicle alignment and site layout. A yard that makes it hard to position buses produces aborted sessions. Phil recommends designing for the largest turning radius in the fleet, with margin, because more agencies now run buses from several OEMs. Catching this in design is far cheaper than fixing it after construction.

2. Charger-to-bus communication. Each bus has to connect to the correct pantograph. Edmonton Transit Service’s Kathleen Andrews Transit Garage, the first transit facility in North America with overhead chargers indoors, pairs buses and chargers using RFID and Wi-Fi.^3,4 Phil notes that buses triggering the pantograph in the neighboring lane still happens at some depots today, which is why communication protocols and spacing between positions need attention in design.

3. Interoperability between bus and charger OEMs. If a charger and bus have not been tested together before delivery, “the agency becomes the guinea pig,” Phil says, while new buses sit idle. Camber runs interoperability tests in the lab before equipment ships so on-site commissioning is verification, not discovery.

4. Underestimated commissioning. Commissioning involves hundreds of checks across every piece of hardware, from terminations to torque. When an agency budgets two weeks and finds a fault, root cause analysis and replacement parts can add months.

Is pantograph charging right for your fleet?

A pantograph is a precision tool, not a default choice. “Understand fit before you select the technology,” Phil says, rather than choosing it because it sounds future-proof.

Sometimes the honest answer is plug-in. Phil describes an older garage in the Northeast without enough ceiling clearance for a standard pantograph, which needs about 4 feet of travel to deploy. A shorter-deploy unit was heavier and raised roof reinforcement costs, so the project moved to plug-in charging.

Before committing, agencies should be able to answer these questions:

• Fleet and schedule: How long are your blocks, and how much dwell time do buses have overnight and at layovers?
• Depot space and structure: Do you have room for safe bus maneuvering, and enough ceiling clearance and structural capacity for overhead equipment?
• Vehicle mix: Will you run buses from more than one OEM, and have those buses been tested with your chosen chargers?
• Labor: Do you have staff to plug in buses, or does hands-free charging save meaningful labor?
• Power: How much capacity does your site have today, and how long will utility upgrades take?
• Maintenance: Can crews safely reach each unit to service hydraulics and clean contact rails?
• Climate: Will equipment face extreme cold, heat, flooding, or salt air?

Phil’s final point is about partners. “Experience in integration, interoperability testing, commissioning, and long-term operations is what makes a complicated technology dependable.”

Planning a pantograph or depot charging project?

Sources

1. Business Wire, “LA Metro Taps Camber Charging to Electrify Bus Network in Time for 2028 Olympics,” May 2026. https://www.businesswire.com/news/home/20260504683551/en/LA-Metro-Taps-Camber-Charging-to-Electrify-Bus-Network-in-Time-for-2028-Olympics
2. SAE International, “SAE J3105 Standard Promotes the Safe Testing and Performance of Mechanized Conductive Power Transfer Systems,” January 23, 2020. https://www.sae.org/news/press-room/2020/01/sae-international-publishes-updated-standard-for-on-route-mechanized-conductive-ev-charging-systems-for-buses
3. CTV News Edmonton, “Smooth riding: Edmonton’s first-ever battery-electric bus rolls into service,” August 2020 (citing the City of Edmonton). https://www.ctvnews.ca/edmonton/article/smooth-riding-edmontons-first-ever-battery-electric-bus-rolls-into-service/
4. Mass Transit, “Edmonton Transit Service unveils electric buses and new garages,” July 2020. https://www.masstransitmag.com/bus/vehicles/hybrid-hydrogen-electric-vehicles/press-release/21147540/proterra-edmonton-transit-service-unveils-electric-buses-and-new-garages