Answer:
Because the passenger demand was not met and also the service was very slow.
Step-by-step explanation:
Although rail passenger transport continued to decline during the Great Depression, new, more aerodynamic and faster diesel-powered locomotives appeared, such as the brilliant 1934 Pioneer Zephyr. This led to many passengers re-trusting the railways. In 1939, 90 high-speed trains were operating, which contributed to a 38% increase over the 1932 level in passenger traffic.
During World War II, restrictions on the use of automotive fuel and troop movements led to an explosive growth in rail passenger transport. The railway companies were struggling to find enough seats to meet demand.