On 23/3/19 12:13 pm, Mal Rowe wrote:
> On 23/03/2019 10:13, Prescott wrote:

>> There would be four more seats in these CAF trams if it wasn't for

>> the design mishap.

>

> The 'mishap' is at the level of the truck design.

>

> The grey rectangles on the attached image - from the brochure - are

> occupied by springs and other bits of the truck.


https://tdu.to/i/64224

Taken in Newcastle on the opening day. The intrusion into the passenger
space is the springs, that for some reason are above the motors instead
of out on the bogie corners where they could some up between the seats -
the solution chosen by Bombardier and Alstom.

Part of the 'problem' is the abandonment of the hub motor idea ABB
developed for the Variotram. The Variotram motor bogie has space for the
springs between the wheels. Other 'modern' designs do not because the
motor is there.  Škoda have since redeveloped a new hub motor design
that doesn't have the unsprung weight problem of the ABB design.

>

>

> At least the CAF design avoids the problem with the centre (presumably

> un-powered) truck.


No motor, so the springs can be lower.