Tens of thousands of Indias too were recruited for building Railways in British Africa notably, Kenya, Uganda and Tanzania(then Tanganika). They were generally well treated and were covered by guarantees of pay and return to home land. Most of them chose to stay back and became traders and Government servants till thrown by Idi Amin.

That is how these three countries were the only British territiries to adopt One meter gauge against 42 inches of the rest of British Africa.

A smaller number were also recruited for the present day South Africa, Zambia and Zimbabwe.  

Railroads have been a driving force behind migration in many places, and immigrant labor was well-treated and/or treated badly, depending on the government and mores of the "host" country.  In the U.S., as most of us know, Chinese were brought in to build the Central Pacific to its junction with Union Pacific at Promontory.  UP used Irish immigrants for its construction.  Neither was particularly welcome or treated very well.  Britain appears to have been somewhat more benevolent as a colonial power in Africa than were France, Belgium, Italy or Germany.  And, speaking of immigrants and history, there was a large migration of Mennonites of German heritage from Czarist Russia to Kansas around the time of the Crimean War.  The Mennonites were under the Kaiser's protection and not subject to conscription into the Russian army, but various alliances caused the Kaiser to relinquish his role as protector of the Mennonites and the Czar planned to conscript lots of young Mennonite males into his army.  Along came land agents of the Santa Fe railway with thousands of acres of land grants available to those who would farm them.  Hence, a sizable Mennonite population residing in Kansas.  Similarly, Mormons formed units of the U.S. Army to fight in the Mexican War in the hope of getting better treatment for their fellow Mormons and themselves back in Utah.  

While the story is compelling, I am disappointed both the author and editor didn't notice a glaring chronological error.

The article states: ...were recruited to build Canada's railroads at the turn of the late 18th Century..."

Sorry, late 18th century was before steam powered railroads were invented, a one-hundred year error.

... awww, gee, what's a 100 years more or less...