Final answer:
The Intercolonial Railway would be supported by a lumber producer in New Brunswick, a stove manufacturing factory in Sarnia, and a shareholder in the Grand Trunk Railway due to its promise to facilitate trade, expand markets, and enhance investment value respectively.
Step-by-step explanation:
The Intercolonial Railway was a significant project aiming to connect various regions of Canada, which would likely garner support from different stakeholders for various reasons. A lumber producer in New Brunswick would support the railway to facilitate the distribution of their products across Canada and potentially to export markets. With the railway, they could reach new markets more easily and expand their business operations. A stove manufacturing factory in Sarnia, Canada West, would likely be in favor because it would reduce the cost and time of shipping their products to consumers and retailers in distant regions, increasing their customer base and making their products more competitive. Finally, a shareholder in the Grand Trunk Railway would likely support the completion of the Intercolonial Railway if it meant an increase in the value of their investment through new business opportunities and partnerships afforded by the expanded railway network.