What vital invention did Elijah McCoy create in 1872 to allow trains to run for longer periods without stopping for manual oiling?

Answer

Automatic lubricator

Elijah McCoy developed an automatic lubricator for steam engines in 1872, which drastically increased operational efficiency by reducing the need for manual stopping to oil the machinery.

What vital invention did Elijah McCoy create in 1872 to allow trains to run for longer periods without stopping for manual oiling?
inventionTransportationimprovement