Supplied by dealer Sherwood Truck & Van, each Stralis has a Cursor 11 engine delivering up to 420bhp between 1,600 and 1,900 rpm, and up to 1,900Nm of torque between 900 and 1,550 rpm.
The vehicles were also specified with Iveco's 12-speed fully automated EuroTronic transmission.
Feedback on the trial vehicle was "very positive", confirms Steve Davis, TNT's national engineering manager.
"In addition to its good fuel economy, we heard only good reports on maintenance and reliability, while drivers also praised the cab."
Fuel efficiency, says Iveco, comes from HI-SCR, its high-efficiency selective catalytic reduction system, which achieves lower emission levels without the use of EGR (exhaust gas recirculation).
According to the manufacturer, this is a less complex yet highly efficient technology, which delivers weight reduction, lower exhaust temperatures and better durability.
The new Stralis AT440S42T/Ps will operate with dry freight box van trailers from three locations in the south – Byfleet, Alton and Southampton – to other TNT hubs throughout the UK.