When it launched Stralis NP (Natural Power) back in 2016, Iveco broke new ground by introducing a tractor unit capable of long-haul work that ran 100 per cent diesel-free.

With a quoted range of 1500 km (932 miles) per fill of the 4×2’s enormous LNG (liquified natural gas) tanks, the truck offered a level of autonomy that couldn’t be sniffed at – and it signalled the first genuine alternative to diesel for long-distance hauliers wishing to reduce both their emissions, and their fuel bills.

Stralis NP launched with a Cursor 9, 8.7-litre, 400 bhp engine and Eurotronic gearbox, and regular readers may recall we tested its chops on a 1347 km (837 mile) trek from John O’Groats to Land’s End back in April 2017. The truck made it with gas to spare – though we felt the early model was a tad underpowered in the hillier parts of Scotland and Cornwall, and the Eurotronic gearbox was a bit sluggish. But despite the niggles, there was no doubting Stralis NP’s achievement.

Fast-forward to 2018 and the NP range has been bolstered with a bigger, 460 bhp powerplant mated to a new, faster and smoother-shifting Hi-Tronix (ie, ZF TraXon) gearbox. Iveco reckons the fuel efficiency from the new driveline has boosted NP460’s total operating range to 1600 km (994 miles) per fill – another headline-grabbing claim. But could the truck bare it out in real-world conditions?

We decided to put it to the test on another epic road trip which would this time stretch Stralis NP to its very limits. If Iveco claimed its flagship gas truck could do 1600 km pump-to-pump, how would it fare on a 1670 km journey from the Italian manufacturer’s offices on the outskirts of London and across the Continent to its manufacturing plant in Madrid?

A route was worked out that would take three days and use the toll roads across France and Spain. On the first day, we’d take the ferry across the Channel and then head south on the A16/A28 around Rouen, past Le Mans and on to an overnight stop at Tours.

Day two would start on the A10 down to Bordeaux, where we’d pick up the A63 bound for the French/Spanish border at Irun. There, Stralis NP would have to tackle the edge of the Pyrenees through San Sebastián to our second overnight stop at Vitoria-Gasteiz.

The final day would send us south on the E-80/E-5 straight down to Madrid. Totting it all up, the total distance covered would be 1670 km (1038 miles). A fair old trek on a single fill!

Ready to roll

We pitched up to Iveco’s site in Basildon early on Monday morning to find the truck topped up and ready to go. Its tri-axle trailer had been stuffed with sand bags to 30 tonnes, its twin gas tanks had been carefully brimmed with 410 kg of LNG – and climbing Into the AS cab, we found the under-bunk fridge had been filled with a fine selection of choccy bars, bottles of water and Coke Zeros. We were all set, so at 0545 we rolled out of the yard and headed for Dover.

Heading for the M25 and the Dartford Crossing, traffic was already getting heavy. The decision was made early on to set a steady, but economical pace, so we set Stralis’ Predictive Cruise Control (PECC) to 52 mph (84 kmh), with +4 mph overspeed so Eco-roll could make the most of any downslopes. This should gain us around 2-3 per cent better fuel economy and increase NP’s chances of making it to Madrid without spluttering to a halt with empty tanks.

Once past the bridge, we swung South East down to Dover and the traffic started to clear and we arrived to catch the 0835 ferry to France in plenty of time.

Continental shift

Disembarking in Calais, things went a bit pear-shaped as we missed the ramp leading to the highway and instead wound up battling through the centre of town. Acutely aware we were wasting gas, we pushed on through the busy streets and finally made it onto A16.

Once passed the péage, the toll road offered a quiet, flat and comfortable run along the coast to Abbeville, where we swung onto the A28 bound for a truck stop 50 km past Rouen. Parked up at the roadside stop, the trip computer reckoned NP was using an average of 23.3 kg/100 km of LNG. Iveco had worked out the viability of the trip based on us achieving an estimated average of 25 kg/100 km – meaning we were currently ahead of the game.

Back on the road, the final push took us down the A28 to Tours. Again, traffic was light and we made good time and we noted how Stralis NP’s TraXon 12-speed automated gearbox gave a very comfortable drive. Coupled with the powerful five-stage ZF Intarder, we barely had to lift a foot, with PECC keeping progress steady as we concentrated on the (admittedly flat and quiet) road ahead.

Pulling up at the Iveco dealership in Tours where the truck would be parked overnight, the tanks were still 3/4 full despite our error in Calais. Not bad going for the first leg.

Into Spain

Tuesday morning, we programmed the sat nav for the push down to the Spanish border and set off from the dealership. Pulling onto the main road, the sat nav told us to make a U-turn at a junction to head to the A10 toll road – but with traffic mounting as students and busses arrived en mass for a nearby college, we decided to press on and find a better place to turn. Unfortunately, the next roundabout was a few kilometres away, meaning more gas wasted in stop/start traffic. Not a good start to the day!

Once on the A10, the road was clear all the way to Bordeaux, where we skirted the city and pulled in for lunch soon after joining the A63. The needle was sitting at just under half a tank – about right, as we were just about half way to Madrid.

The afternoon drive would take us across the Spanish border at Irun. Clearing the péage, we could see mountains on the horizon and sure enough, we were soon rising fast into the hills. The scenery was marvellous, though the truck was working hard. There were no complaints at all from the 460 bhp engine at this weight and NP climbed with ease – but what alarmed us was the live fuel reading showed we’d started to burn gas at a rate of 90+ kg/100 km on some of the steeper ascents! We couldn’t take much of this if NP was to make it to Madrid on its remaining gas.

But what goes up, has to come down – and on the steep descents, NP’s powerful Intarder came into its own, holding the truck steady the entire way without us needing to use the brake.

After an impressive drive across the edge of the Pyrenees, we arrived in Vitoria in the early evening. By now, the needle was down to just over quarter-full. Hopefully, the road to Madrid would be flat as a pancake tomorrow.

More ups & downs

Pancake-like, it was not. Setting off early on day three, it was rainy and foggy as we took the E-80 South West to Burgos. The highway rose and fell dramatically all the way as we crossed more mountains. Taking the E-5 due South for the final push to Madrid, we pulled in for a coffee at Grajera – just as the fuel warning light came on. A glance at the map showed we still had 130 km to go. Gulp.

Pushing on along the undulating E-5, the weather was getting worse as the ECM warning lights came on at the outskirts of Madrid. Pressure in the two large tanks had dropped dramatically and the engine was starting to struggle. After a few more kilometres, we spotted Madrid airport off to the right – our final destination was a BP/Molgas filling station, which was right next to it. But we couldn’t relax yet, as there was the small matter of a long, steep climb on the R-2/M-50 around the city to contend with first.

By now, the engine was properly suffering. Flicking on the hazard lights, we slowed to a 20 kmh crawl as the NP struggled on up the hill. We were very close to calling it a day, but the brow was in sight – and after a nail-biting few minutes, we were rolling down the other side to the exit ramp.

Making the most of the truck’s inertia, we took the turn-off, offered silent thanks as we managed to roll up to and around a couple of roundabouts without having to brake, and then crawled onto the filling station forecourt as NP’s gas reserves petered out.

The truck had made it. The trip computer showed our total journey as 1728.2 km (1074 miles) – surely a world record for an LNG-fuelled truck on a single fill.

Verdict

If nothing else, NP’s record-breaking run shows Iveco is not afraid to put its money where its mouth is. Over 1700 km on a single fill is a formidable achievement and proves without doubt that operators looking for a cleaner (and ultimately cheaper) long-haul alternative to diesel should take a serious look at LNG.

But alongside going the distance, Stralis NP also gave us a very comfortable drive. The 460 bhp motor and Hi-Tronix gearbox make the ride smooth and effortless for the driver, and the powerful Intarder is more than capable of handling the lion’s share of braking without intervention. The gas engine doesn’t provide as much fine throttle control for low-speed shunting in the yard, but we’d challenge any driver to spot the difference in performance once out on the highway.

Operators considering their green credentials should certainly take a long look at what Stralis NP has to offer.