Robbins TBM hailed as world’s ‘fastest’ over 13m diameter

The 13.77m XRE TBM has now set triple world bests, beating its own records in May and June with a set of more records over the summer, including a best day of 32.4m, a best week of 178.2m and a best month of 721.8m.

Launched in March 2021, the machine bored 3.05km on the Esme-Salihli Railway Tunnel as part of the Ankara-Izmir high-speed railway project for the TCDD.

Having begun its bore in altered gneiss, the machine then passed through a mélange comprising gneiss, sandstone, claystone, mudstone, quartz and silt. By the end of the bore the machine was excavating in mainly mudstone. Core drillings were taken every 200m prior to boring so the crew felt confident with the geology – just one of several factors thought to have contributed to the record rates.

“We have disproved the idea that it is difficult to reach high advance rates while boring in EPB mode with large diameter TBMs,” said Onur Kansu, TBM manager for Kolin Construction. “Crossover TBMs enable us to find quick solutions in changing ground, so we believe they will be the preference for future projects.”

With tunnel excavation finished, work will continue on the 508km line that will connect Polatli in Ankara Province to Izmir. Once complete, the Ankara-Izmir high speed railway will be the longest rail line in the country, conveying passengers at top speeds of 250km/h in a journey of around 3.5 hours.