In which year did Genesee and Wyoming complete the acquisition of its 100th railroad?

The acquisition of the 100th railroad by Genesee and Wyoming is an important milestone that reflects the company's growth and expansion strategy in the North American railroad industry. This momentous occasion occurred in 2018, marking a significant achievement for the company as it reached a substantial scale in operations and network reach.

Genesee and Wyoming's strategy has included the continuous acquisition of short line and regional railroads to diversify its portfolio, enhance operational efficiency, and broaden service offerings. By 2018, they had established themselves as one of the leading operators in the sector, which was underscored by this 100th acquisition.

The other years listed do not correspond with this milestone in the company’s history. While 2015 and 2010 were years during which Genesee and Wyoming may have completed acquisitions, they did not achieve the 100th railroad until 2018. Similarly, 2020 is a year that falls outside the timeline of reaching that key milestone. Therefore, the correct selection is the year 2018, as it accurately reflects the point at which Genesee and Wyoming completed the milestone of acquiring its 100th railroad.