Motovated Case Studies

P11 Bogie Design & Analysis for KiwiRail


Late in 2009 KiwiRail commissioned Motovated to engineer a bogie in support of their new Tranz Scenic rail cars. These rail cars were due to be delivered in early 2011 and were to be a significant step forward in terms of ride quality for KiwiRail. As such the requirements for the new bogie’s ride, maintainability and durability were high, and the timelines tight. Bread and butter for Motovated!

Bogies are effectively the connection between the rail car (or carriages) and the track. They carry the wheels, axles, brakes and suspension, and isolate the passengers from noise and vibration. As such they were critical to the success of the new cars, especially on the challenging showpiece lines of the TranzAlpine and Costal Pacific routes.

Adding to the challenge was the need to develop new suspension technologies including a new axle box in support of the tight space constraints imposed by under carriage clearance issues.

The Solution:

In conjunction with rail specialists Interfleet Technology and KiwiRail’s Mechanical Design Group; Motovated went through an extensive design optimisation process to ensure the ride quality and safety requirements were met, all within the tight design constraints required. Once the dynamics were optimised a significant strength and manufacturability exercise was undertaken to ensure maximum life at minimum cost.

Motovated worked closely with the Mechanical Design Group for validation of their stress analyses and KiwiRail’s Hillside Engineering Group with respect to manufacturability. Finite Element Analyses (FEAs) were used for validation of the MathCAD stress analyses, including fatigue. The frame was especially challenging due to the extensive welding analyses required, while the axle box presented its own challenges due to the inherent flaws in steel castings.

Motovated then worked with Holmes Solutions to actually physically test their designs, validating the 25 year minimum design life up-front. Strength assured!

The Result

The synergy between Motovated, Interfleet, Holmes Solutions and KiwiRail’s Mechanical Design Group & Hillside Engineering provided a phenomenal solution to a challenging problem.

Kiwi Rail Bogie Design & Analysis by Motovated

KiwiRail’s new P11 Bogie Rendering

FEA on KiwiRail Bogie by Mootovated

Fabricated Frame FE Stress Analysis


Cast Steel Axle Box Rendering