GWR's New Battery Powered Train

Step by step we move away from fossil fuels in railways. 

 Electrification is overall cheaper on busy lines. To date, diesel has been cheaper on less-used lines, because the higher capital cost of installing third-rail/overhead-wire technology isn't offset by the cheaper running coats of electricity.    

I've talked before about battery-powered electric trains which charge from the overhead catenary when they travel on track with electrification, allowing them to travel some way on un-electrified track. 

 Which of these alternative approaches would be better would depend on distances travelled and how fast overhead catenary-charged batteries can charge.  In Australia, for example, rural towns are much further apart than the towns served by this line in England, which are roughly 5 miles apart.   This would require more batteries, on the train and next to the track, and more charging time.  

An alternative is a locomotive which can run on either diesel or electric power, called "electro-diesel" or "bi-mode"  locos (not to be confused with diesel-electric motors), such as the new trains in NSW (which I know I wrote about here on Volewica, but have been unable to find the article)