It hasn't been a smooth ride for London Mayor Boris Johnson's flagship New Bus for London, or as it has been more recently rebranded the New Routemaster.
At the moment there are 700 in service. And putting aesthetics to one side, technically there have been problems and now we can reveal there have been more - this time concerning the power steering.
There were reportedly excessive levels of heat on the top deck and only recently have Transport for London (TfL) bosses given ground to concerns at City Hall and allowed the installation of Windows that can be opened for ventilation.
Driven by diesel or "clean and green".
The 21st Century Routemaster bus is making drivers see red. It's been alleged that at the back of a certain bus depot, there is a large pile of power batteries that no longer work. All have been removed from the new bus for London and are a crucial part of the hybrid system.
Drivers say that many buses across London are operating without them in place.
This means in some cases, what Transport for London (TfL) claims is "the most environmentally friendly bus of its type" is running solely on diesel.
In another embarrassing revelation, we've been told wiring in the power-assisted steering has had to be replaced in 468 of the new buses.
It means a recall notice has been issued by the government's Vehicle and Operator Services Agency (VOSA), as the "power assisted steering may become non-functional".
The replacements were carried out by the manufacturer Wrightbus at London garages between October 2015 and February 2016.
Critics say the whole New Bus for London scheme is nothing more than a rushed vanity project.
It would have been far more sensible to buy cheaper existing hybrid buses.