New Routemaster runs out of fuel

[Bobjork]

http://www.bbc.co.uk/news/uk-england-london-16244634

Got this link posted on my facebook.
Out of fuel is something that happens sometimes, if the routines for refueling fails.
But one thing that seems strange is that on long journeys the batteries may become uncharged and you need to stop in order to charge the batteries.
How can you build something stupid like that? Isn't it better to vharge the batteries with the engine, like Volvos hybrid buses do? (Ok the Volvo hybrid only uses batteries in speeds lower than 20 or 30 km/h. But if you go at that speed and the batterie power becomes low, the engine starts.
And how does the batteries charge when the bus is stopped?
The bus in the article had no diesel, but still it recharged when the bus was stopped?

http://www.truckandbusforum.com/gall...age.php?i=8038
Volvo 7700 Hybrid.