President Xi Jinping's ambitious Belt and Road Initiative (BRI), launched in 2013, aims to connect two-thirds of the world's population across 70 countries through a network of land links (the "belt") and sea routes (the "road"). Officials talk about lifetime investments worth trillions of dollars, sourced from banks, participating countries and the Chinese government.

How do you build high-speed railways quickly where large sections of route must be suspended over valleys and canyons to avoid bends?

The tried and tested method of bridge building using cranes has been well and truly shaken by a pioneering piece of new technology that is currently fascinating industry watchers.

Enter bridge-building machine SLJ900/32 - locally nicknamed the Iron Monster, manufactured by Beijing Wowjoint Machinery Company and designed by the Shijiazhuang Railway Design Institute. This behemoth weighs in at a 580 tonnes, is 91 metres long and 7 meters wide. With the help of its 64 wheels it returns to collect another block, then rolls forward over the part it has just laid to place another section.

The SLJ is an all-in-one machine capable of carrying, lifting and placing sections of track, connecting pillar to pillar with heavy stone blocks, without the need for expensive and complex scaffolding and framework structures.

This is how it works: https://www.youtube.com/watch?v=cKi8VWRDA_c

Each wheel is in a fully rotating block of 16, meaning it can also move sideways, and with a full load it can move at 5km/h (3mph), ensuring that the whole process is much quicker than traditional methods, which needed enormous cranes to be built on the ground.

The SLJ is currently in active use in China for the construction of large and high rail viaducts, most notable between Chongqing and Wanzhou in the province of Sichuan, as well as a new link between Inner Mongolia and the rest of the country. Due to the immense weight of the machine, these bridges are made to be far bigger than necessary and hence capable of taking far heavier traffic and weight loads than the rail networks for which they are intended.

The fact that this concession seems to be being made across China speaks volumes about the way in which the SLJ is perceived within the industry, propelling China towards its goal of 30,000km of high-speed rail by 2020.