They have much less damage inflicted to units compared to a Miner. It is suggested not to use this unit for attacking other units.
"In the mid-nineteenth century, the discovery of gold in California and the need for efficient postal routes led to interest in building a transcontinental railroad across North America. Initially, a shortage of workers made construction of the railroad difficult. Soon veterans of the Civil War swelled the ranks of the workers and allowed the Union Pacific Corporation to complete its railroad across over 1,700 miles of wilderness in less than four years. The railroad workers faced low wages and difficult working conditions; labor strikes were common. Union Pacific broke the strikes by bringing in Chinese workers to complete the railroad."