Tourist railroads are one of the unexpected pleasures of travel.
Usually operating on trackage that railroads no longer need, they offer low-speed rides through scenic vistas, including locations that tourists often can't reach by car.
But along with historic railcars on many lines come older engines, usually powered by diesel engines decades old without a single piece of emission-control equipment.
Enter the Börzsöny solar-powered electric passenger railcar.
As noted earlier this month in the Railway Gazette, the experimental railcar has a top speed of 16 miles per hour (25 km/h) and is intended for use on a 7.5-mile (12-km) line from Kismaros to Királyrét in Hungary.
It seats 32 people, and its roof is covered with 106 square feet (9.9 square meters) of photovoltaic solar cells.
Photovoltaic solar power field at Volkswagen plant in Chattanooga, Tennessee
These charge a battery pack of unspecified capacity, though it is said to be sufficient for four or five uphill trips along the line.
The returning leg, downhill, requires little energy, although the article doesn't mention whether regenerative braking is used to recapture the car's otherwise wasted momentum on the return trip.
The battery can also be plugged into the electric grid to recharge overnight.
The solar electric rail car is roughly 27 feet long and 6.6 feet wide, running on 760-mm (2.5-foot) gauge rail track, a narrow-gauge standard used in the former Austro-Hungarian Empire and known as the "Bosnian gauge."
The frames and mechanical parts of the solar railcar were supplied by Börzsöny 2020. The electrical systems were provided by Hungarotrain, while GanzPlan contributed documentation.
[hat tip: Dave Baker, Delaware & Ulster Rail Road]