W Class Tram Modernisation

The traction chopper system was designed in such a way to provide increased reliability, redundancy and maintainability for the life of the restored W8 class trams. A completely customised housing was designed to fit the system within the available tram structure and kinematic envelope. The system included an LCD message display installed in the driver’s cabin to provide real time status and fault data to the drivers. A maintenance access panel was also incorporated into the design at the customer’s request to allow ease of access to such data as voltage and current monitoring of the system, and motor isolation switches. The traction system was also subjected to shock and vibration testing to rolling stock standard IEC 61373:2010, to ensure the integrity of the system throughout its life.

Installation and commissioning services of the complete system were also provided by TTM Rail. The overall result of this system was an increase in the safety, reliability, efficiency and maintainability of the traction system, while providing a smoother ride for drivers and customers.

The objective of this modification was to provide a safer, reliable and much smaller system to install within the master controllers, while maintaining a similar tactile feedback and heritage visual look. As the existing controller had to be used, off the shelf master controllers were not an option.

To minimise costs for our customer, we opted to use the key existing components, however no original drawings existed for any components of this controller. Our 3D scanning capabilities were utilised to obtain accurate models of the existing components, which were then modified in our 3D CAD software, and redesigned to incorporate a modern control system. The new design comprised of reliable potentiometers coupled to a modified existing main acceleration shaft, and a series of inductive proximity sensors for other feedback signals required.

Two inverters were required for the supply of auxiliary power in each tram. One inverter was used to supply 230VAC, 3 phase power to the braking compressor only. The other inverter was required to supply the 3 phase 400VAC driver’s cab air conditioning system, and the modified single phase 230VAC driver and saloon heaters. The equipment was configured to allow identical inverters to be supplied for both applications, reducing the number of spares required in our customers store.

As with most typical rolling stock, over the many years of service the W class drivers console gradually expanded with the addition of boxes and buttons mounted to the side of the existing console as required. This resulted in a much larger than originally designed drivers console assembly. This can start to impede the driver’s visibility, and create additional hazards in the event of an accident.

TTM Rail was requested by our customer to design a new driver’s console and offside panel assembly, with consideration for improving the aesthetics, reducing the size, increasing the driver’s visibility, including a high mounted brake light, and most importantly improving the ergonomics and function of the design. All of these targets were achieved, with a simple, robust, plug and play box. The interfaces and controls required while driving the tram were included on the front driver’s console to minimise the time the driver needs to take their eyes off the road, while the less frequently used controls were shifted to an offside panel.

As part of the overall target to increase the safety of the vehicle by removing the 600VDC from the drivers cabin and saloon, and increasing the lighting for passengers, our customer requested that TTM Rail design and supply an efficient 24VDC LED saloon light to replace the original 600VDC lighting system. While simple on its own, a challenging task was created when the following requirements were also requested. The lights were required to:

• Utilise efficient 24VDC LED lights
• Maintain the same light colour as the original globes, while increasing the luminosity to assist meeting current rolling stock standards for vehicle lighting
• Use the same mounting points and maintain the same external heritage look and glow of the original lights.

The existing heaters were originally operated from a 600VDC supply. To increase the safety of the vehicle, an overall requirement of removing the 600VDC supply from the driver’s cabin and saloon was targeted. This involved modifying the existing heaters to operate from a combination of 240VAC (saloon heaters), and 240VAC/24VDC (Driver’s Heaters).