We owe the colorful Americanism "jerkwater" to the invention of the steam engine-an advancement that significantly accelerated travel by rail but also had its drawbacks. One drawback was that the boilers of the early locomotives needed to be refilled with water frequently, and water tanks were few and far between. As a result, the small trains that ran on rural branch lines often had to stop to take on water from local supplies. Such trains were commonly called "jerkwaters" from the motion of jerking the water up in buckets from the supply to the engine. The derogatory use of "jerkwater" for things unimportant or trivial reflects the fact that these jerkwater trains typically ran on lines connecting small middle-of-nowhere towns.

Examples

"We're stranded in some jerkwater town in the middle of nowhere," said Larry when he called to tell us that the car's engine had blown.

"Hardworking and reserved, Jesse might use five words when the situation called for nine. The son of Mexican immigrants, he was born in the cheerless, jerkwater town of Firebaugh, Calif., in 1938; facts that undoubtedly contributed to his abiding humility." - From an article by Scott P. Charles in the Philadelphia Inquirer, June 12, 2012