Switching from diesel to electric traction is leading to big maintenance savings for bus and coach operators – as well as changes in workshop practice. With electric vehicles typically requiring 30% to 40% less maintenance than anything with an internal combustion engine, fewer technicians are required, says Keith Bradbury, co-founder of Ember, an all-electric coach operator. “Our technicians-to-vehicles ratio is lower than would be necessary if we ran diesels,” he observes.
Ember operates 38 electric Yutong coaches on scheduled multiple-stop inter-urban services across central Scotland and plans to acquire another 100 over the next two years. Destinations it serves include Glasgow, Edinburgh, Perth, Stirling and Dundee. The company maintains its fleet at a central workshop in Dundee and each of its coaches goes there once a month for a scheduled inspection.
With a drivetrain made up of an electric motor and a battery pack, there is far less to potentially go wrong than there is with a diesel with its cylinders, pistons, turbocharger and fuel injection system. “Reducing the parts count means you reduce the complexity – and our electric vehicles are proving to be reliable,” Bradbury comments.
Within the workshop, there is no need to worry about the disposal of waste oil and used oil and fuel filters and no requirement to top up an AdBlue reservoir regularly. Nor is the Ember fleet plagued by problems triggered by faulty emission sensors that can put a diesel off the road until an defect is rectified. “You can have a situation where a diesel vehicle ends up stranded at the roadside because there is a fault with a £5 sensor and it costs £250 to send out an engineer to get it fixed,” Bradbury remarks.
The increasing use of remote diagnosis should mean that this is less likely to happen, but it is not, of course, available on all vehicles. If a bus or coach is stranded, then it is not garnering revenue for the operator. “It’s the downtime that really costs you money,” he says.
BETTER BATTERIES
Safety is paramount when working on electric buses, given the likely consequences of chopping through a live high-voltage cable and the need to follow precautions. “The only technicians who are allowed to go near a coach’s high-voltage system are those who are categorised as high-voltage qualified, and have been on the appropriate safety course,” says Bradbury.
Ember has to pay attention to battery balancing, he adds. That means ensuring all the cells are charged and discharged evenly, thereby ensuring the battery pack delivers optimum performance – and prolonging its life. Yutong has addressed any worries about a battery fire by fitting the cells into a modular pack made from flame-retardant material, which it says will cope with temperatures of up to 1,300°C.
Defended by steel collision protection bars, the pack is fitted with a flame-retardant cover. A thermal runaway of the battery will result in the pack filling with nitrogen, displacing any oxygen and reducing the amount of combustible gas present.
Electric buses still have fluid levels that require monitoring and here Bradbury is thinking about the coolant for the battery pack. Checks have to be carried out to ensure that the brakes, steering and lights are all working properly, that the tyres are undamaged – and their tread depth remains legal.
Ancillary equipment including the air-conditioning system and ticketing machine have to be given the once-over too, while the wheelchair lift has to be cycled. If it sticks, then the vehicle has to be taken off the road until it is repaired.
Much of the foregoing is covered by the daily checks that must be undertaken prior to a bus or coach leaving the depot, no matter how it is powered. Increasingly, these checks are digitised, with Go-Ahead among those operators ditching paper-based reports in favour of smartphone apps that allow defects to be reported in real time, and accompanied by photographs if necessary.
Go-Ahead recently announced that it is doing so using an app developed by Tranzaura, which is scheduled to cover all of the company’s 6,000-plus UK buses by the end of the year. Other operators using the technology include Nottingham City Transport (NCT).
Tranzaura has integrated the app with NCT’s third-party digital workshop management system, which receives the defect reports. Notifications are sent out once the defects are cleared. Before the app was introduced, NCT relied on paper dockets that were collected from drivers every evening – and rectified any faults overnight. Technicians had no idea what defects they would be dealing with until the dockets were handed in, or if any faults would be reported at all. Switching to a digital approach means that the need for staff to work overnight has been reduced by 50%.
NEW RUBBER FOR RETREADING
Returning to tyres, electric buses are being fitted with rubber specifically designed for battery-powered vehicles which can cope with any increases in weight and torque. For example, the 24 zero-emission Alexander Dennis Enviro400EV double-deckers ordered by Reading Buses for delivery next April will be wearing Michelin X InCity EV Z boots.
An existing Michelin customer, Reading Buses has just signed a five-year agreement with the manufacturer’s services and solutions division, which will involve the latter overseeing the supply, fitment and management of all tyres across the operator’s 260-strong fleet. Michelin technicians will mount, demount and inspect all built-up wheel assemblies. The operator will be running on a mixture of new tyres and retreads; Michelin markets the latter under the ‘Remix’ banner.
Reading is already having the newly-launched X InCity EV Z Remix fitted to the drive axles of some of its existing buses. Michelin contends that it is just as effective on non-zero-emission vehicles as it is on their electric counterparts, has similar levels of rolling resistance and mileage potential to the new version, and can stand up to damage – including kerbing damage – just as effectively.
OPPORTUNITY KNOCKS
Getting to grips with the maintenance schedules of electric buses while keeping diesel and possibly biogas-powered models on the highway poses some exciting challenges for youngsters joining the transport industry. While Bradbury has referred to a reduced need for technicians as more electric vehicles come into service, vehicles fitted with internal combustion engines will be around for many years to come – and the career prospects for apprentices look good.
At the time of writing, two apprentices were due to arrive at the First Bus depot in Rochdale, which has recently benefited from a £750,000 investment. The premises now has a double-height workshop bay, two pits to maintain single-deckers, a brake tester, new tooling and an external bay with lifting gear. “All this allows us to take a proactive approach to planned maintenance and introduce new preventive maintenance processes,” says First Bus engineering manager, Aaron Taylor.
First Bus operates more than 30 routes for the much-publicised franchised Bee Network in the Rochdale and Bury area, together with six school services using a fleet of over 65 buses with the capacity to expand the depot to 90 vehicles.
The need for bus and coach apprentices to cope with changes in technology was highlighted at this year’s IRTE Skills Challenge, which was held at S&B Automotive Academy in Bristol in June. The challenges set by Alexander Dennis focused on door systems and reflected how mechanical issues are increasingly intertwined with electrical components, with pneumatic pumps – for example – becoming electrically controlled.
“We want to arm people with the knowledge to go in and diagnose more challenging faults as vehicle systems get more complex and more electrically based,” says Laura Tofts, head of product information and training at Alexander Dennis. “The IRTE Skills Challenge always gives us a great platform to do this outside of our own courses – and the experience informs how we develop our courses further.”
