Vehicles sold because of concerns over particulate traps
A Phil Anslow bus in Cwmbran
A bus operator is selling two of its Euro 6 buses because of concerns over the vehicles’ particulate traps when 20mph becomes the default speed limit on restricted roads in Wales. However, an experienced bus engineer told Passenger Transport there was no need for Welsh operators to sell Euro 6 buses because there were other ways to manage the issue.
From September 17 all roads with street lighting are presumed to be 20mph unless signed otherwise. Many bus operators have expressed concern about the impact on journey times and the resources required to sustain current frequencies. Some have made anticipatory timetable adjustments but most are waiting to see how the increase in 20mph running works in practice before applying for changes to service registrations.
At 20mph, I know our Euro 6 buses won’t be able to clean themselves. We’re going down from Euro 6 to Euro 5.
Pontypool-based Phil Anslow & Sons Coaches is so concerned about the effect of the more widespread 20mph limits on Euro 6 buses that it has decided to replace its two buses which were new in 2020 with older ones. Managing director Phil Anslow said: “At 20mph, I know our Euro 6 buses won’t be able to clean themselves. We’re going down from Euro 6 to Euro 5.”
He said the company was forever cleaning out the soot traps on the Euro 6 vehicles. The engine needed to reach a certain temperature for the system to empty the particulate traps automatically. Anslow said the vehicles would not reach that temperature if their duties involved no sustained running at speeds above 20mph. The company previously had to pay £15,000 to repair one bus after the soot trap became completely clogged up.
An engineer who has maintained buses in one of Britain’s biggest cities agreed that there was a risk of too much soot building up if a bus was always limited to 20mph. The same risk applied where a bus never went faster than 30mph, but the issue would arise more often with 20mph running.
He said: “I wouldn’t sell Euro 6 buses for that reason. If I was running one on a route that didn’t go on any dual carriageway and was always 30mph or less, I would do a run on a motorway or dual carriageway [periodically] to get it up to temperature, or I would do a manual regeneration on a laptop.”
Instructing the system to regenerate manually, however, would require staff time and vehicle downtime. Another option would be to give Euro 6 buses duty cycles which included some operation on inter-urban routes where the limit is 40mph to 60mph.
In his experience, one of the practical difficulties with large numbers of roads having 20mph limits instead of 30mph arose from gearboxes being programmed for 18mph or 22mph. This was solved at his previous company, part of one of the large bus groups, by a software update which ensured the vehicles could maintain a steady 20mph comfortably, without repeatedly changing gear.
Phil Anslow Coaches has registered changes to four of its routes to take effect on September 20 because the journey times will be extended by the decreased speed on 20mph roads. Anslow said he hoped that the impact on some of his other routes could be absorbed by the leeway built into turnaround times, but expected that amendments would need to be registered on some routes once the impact of the speed limit change was visible.
He also said the additional running time would prevent five of his vehicles from serving both a school and a college each morning, as they had done previously. Although the school day begins before the college day, there will be insufficient time for each vehicle to deliver students to a college after dropping off at a school.
This article appears inside the latest issue of Passenger Transport.
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