The NSW road train modernisation program has, as a result of mandating triaxle converter dollies unreasonably disadvantaged at least the better designed air suspension tandem converter dollies. There does not appear to have been consideration for converter dollies operating in more populous areas where they will likely be subjected to an increased frequency of more “significant” (high pressure) braking events due to actions by other road users.
The ATA Industry Technical Council does not share the view that simply changing from a tandem axle converter dolly to a triaxle converter dolly necessarily results in an improvement in dynamic performance improvement nor other safety considerations. Triaxle groups (including converter dollies) generally incur higher maintenance and operating costs than tandem groups. Some operators are moving away from air suspension converter dollies and trending back to mechanical suspensions because of issues experienced with air suspension converter dollies (including triaxle), where the dynamic issues do not significantly change, seemingly just less influenced (especially the braking reactivity) by the mechanical suspension.
The ATA recommends that the NSW Government should review this requirement to ensure that the road train modernisation program prioritises safety and productivity outcomes.