Is it a truck, is it a train? Well it is a hi-railer, which can travel on highways and on railway track. The unit, a Brute 150, carries a CN equipment number: CNU 70634.
Used for re-railing grounded rolling stock, repair and construction work, it was built by the Brute company, and features a Detroit Diesel engine and Allison transmission. Aside from the cab doors, which appear to be purchased items, all the rest was fabricated by Brute.
The brain child of Delmon Isringhausem, who built the first ones from 1978 to the mid 1980s, the Brute business has been sold several times over the years, but the successor is Tandano Mantis, which no longer uses the Brute name.
I saw the unit today in Moncton, NB at Lounsbury's. The boys in the shop claim they are the only ones who know how to keep it running. It does carry Manitoba license plates, so covers quite a bit of CN territory.