Correct, taper only works to a point.
Vienna has Siemens-built Ultra-low-floor LRV’s (the only ones in the world), and they do this. The motors are all servos, and the inboard and outboard ones vary their speed in curves. Vienna hates them, though, because they can’t manually tow them if the control system is off, without them derailing! Bombardier just started delivering new LRV’s to replace them... with conventional axles.
Photo Credit: Paul Bigland. You can see the individual wheel + gearbox + servo arrangement mounted upright between the modules.
The reason FLEXITY Freedom has standard axles is because it lowers the cost and means they can use off-the-shelf bogie components. It’s one of the only 100% LF designs that makes use of a standard axle. Other LFLRV’s use gearboxes and additional dive shafts at a lower centre to allow the passageway above.
Bogie from one of Toronto's FLEXITY Outlook LRV's; this bogie is virtually identical to ours, albeit a little wider. Photo credit: me!
Vienna has Siemens-built Ultra-low-floor LRV’s (the only ones in the world), and they do this. The motors are all servos, and the inboard and outboard ones vary their speed in curves. Vienna hates them, though, because they can’t manually tow them if the control system is off, without them derailing! Bombardier just started delivering new LRV’s to replace them... with conventional axles.
Photo Credit: Paul Bigland. You can see the individual wheel + gearbox + servo arrangement mounted upright between the modules.
The reason FLEXITY Freedom has standard axles is because it lowers the cost and means they can use off-the-shelf bogie components. It’s one of the only 100% LF designs that makes use of a standard axle. Other LFLRV’s use gearboxes and additional dive shafts at a lower centre to allow the passageway above.
Quote:It runs on BOMBARDIER* FLEXX* Urban 3000 bogies
that were specifically developed for this 100% low-floor
vehicle, featuring conventional axles with primary and
secondary suspension elements. A hydraulic load-leveling
system that adjusts to boarding platforms completes the
design.
Quote:Bombardier was the first in the industry to combine 100%
low-floor technology with conventional wheel-set bogies.
Besides making low-floor entrances and easier passenger
access possible, this leading-edge technology gives the
FLEXITY Freedom ultra-smooth running qualities.
Bogie from one of Toronto's FLEXITY Outlook LRV's; this bogie is virtually identical to ours, albeit a little wider. Photo credit: me!