What primary problem did the adoption of a 'standard gauge' solve for the 19th-century railroad industry?

The high cost of steel used for making rails

Incompatible track sizes between different companies' lines

Frequent collisions caused by a lack of standardized train signals

The inability of early steam engines to climb steep mountain grades

What was a direct economic consequence of creating an interconnected national railroad network with a standard gauge?

It increased the price of coal.

It ended the use of steamboats.

The inability to stop reliably, leading to accidents

The frequent breakdown of steam engines during long journeys

The high probability of tracks washing out during heavy rain

The difficulty of communicating between distant train stations

A decline in westward expansion as people preferred to stay in eastern cities.

The creation of a truly national market where goods could be sold across the country.

A shift in the American economy away from manufacturing and back toward local farming.

The replacement of all railroads by canals and riverboats as the primary means of transport.