Israel Railways has resumed work on the country's two longest tunnels nearly three weeks after finding a 60-centimeter deviation from the planned route of the Tel Aviv-to-Jerusalem high-speed-rail line.

The cause of the deviation in the twin 11.6-kilometer tunnels is still under investigation by Israel Railways, Israeli contractor Shapir Civil and Marine Engineering Ltd. and the Italian operator of the project's tunnel-boring machines.

"The solution ... involved a realignment of the TBM and will not have any impact on the route or project timetable," says Dror Sofro, Israel Railways project director. He says it is still unclear what caused the problem, which continued for several dozen meters before being discovered.

Work on the twin tunnels began last year and is set to finish in early 2015, with the first trains running by the end of 2017. Trains already are running on other sections of the rail line.

Local press reports cited possible errors in the coordinates that were fed into the computer of the TBM, which is being used in Israel for the first time.

Previous tunnel work on highway and rail projects has involved traditional drill-and-blast techniques. The problem occurred in a tunnel section considered to be the longest and most complex of the $2-billion, 56-km-long electrified line. The section includes a separate 1.2-km tunnel and a 150-m bridge.

Work also was delayed by an unrelated accident in August that killed Shapir senior engineer Yossi Einbinder, 56, who was in charge of project operations for the firm. An initial probe found that he slipped and fell on the line inside the tunnel as a rail car was passing.

Work on the twin tunnels began several years behind schedule because Israel Railways had issued the tender for the section before it received all necessary permits, forcing Shapir to switch tunneling firms.

Russia's Moscow MetroStroy is working for contractor Minrav Holdings Ltd. on a separate 3.5-km tunnel section, while Germany's Max Bogl Group runs tunneling on another 2.29-km section for Hofrey Hasharon Ltd. The latter includes two bridges and a 2.29-km-long tunnel at the Jerusalem terminus.