Why was it impossible to travel on train from one end of the east coast to the other in 1835?

I believe it is because it was expensive, and the U.S was independent from Texas. Mexico also held the west coast, and pretty much everything was in Kaos, because Texas Independence.

Explanation:

Mexico held what is now known as Arizona, California, New Mexico, Texas, Colorado, Nevada, and Utah, which is pretty bigg.

Mexico and Texas wasn't getting along, and the U.S was slightly supporting the U.S so that didn't go over so well.

President Houston tried to smooth things over with Polk, but Lamar kinda went banzai and attacked everything and tried to Manifest Destiny Texas instead of the U.S, and Lamar hated joining the U.S, and Mexico said that if Texas joined the U.S, "Texas + U.S = war." which kinda blew up into war.

answer: (fluidity)is the correct answer.

explanation: because of this characteristic, success on the battlefield depends in large part on the ability to adapt to proactively change events to our advantage as well as to react quickly to constantly changing conditions