Which type of engine replaced steam engines in fire fighting beginning in 1907?

The correct answer is internal combustion engines, which began to replace steam engines in firefighting around 1907. The shift to internal combustion engines marked a significant advancement in fire apparatus technology. Internal combustion engines allowed fire trucks to become more mobile and agile, significantly improving response times compared to steam-powered engines, which required time to build pressure and could be cumbersome.

In addition, internal combustion engines were easier to maintain and operate, providing a reliable source of power that didn't depend on the need for water boilers or extensive crew to operate. This evolution in engine technology facilitated quicker deployments and greater efficiency in handling emergencies, contributing to the modern fire service's ability to respond rapidly to incidents.

While electric and hydraulic engines have their uses in certain applications, they did not become the primary power source in firefighting during that era. Diesel engines also emerged later and became popular, but the transition from steam engines primarily involved the adoption of internal combustion engines first.