In 1877, J. E. Wooten introduced his Camelback locomotive. It was equipped with a large firebox, which, however, only allowed for an extremely limited workspace behind it. The only solution that made any sense, therefore, was to move the engineer's cab to the front. As a result, the fireman had to stand on an unprotected platform at the end. Later, the Camelback was given a small roof to protect the fireman. All the same, working on a Camelback remained dangerous.

The first Consolidations were built for the Lehigh & Mahanoy Railroad in 1866.
This type of locomotive was called Consolidation in honor of several smaller railroad companies that had merged to become the Lehigh Valley Railroad Company.
Thanks to its better tractive power, this type of locomotive soon replaced the older engines and became the most widely used locomotives in freight trains between 1900 and 1910.

In 1836, William Norris built the "Philadelphia", a 4-2-0 with a truck and a funnel-shaped chimney. This was to become the prototype for many ensuing six-wheeler models.
This locomotive wasn't equipped with a closed driver's cab yet.

These locomotives have a steam reservoir that is charged with steam and hot water from a stationary facility. They were employed near powder factories, lumberyards, sugar refineries, and other industries where sparks and smoke could easily kindle a conflagration.

The first 2-6-0 Mogul locomotive appeared in 1852. It had a rigid frame and was the first locomotive with a swiveling lead truck. Baldwin produced it for the Louisville & Nashville Railroad in 1870. The Mogul has 50 percent more tractive power than the 4-4-0 American.