Seesaw a "teeter-totter". According to linguist Peter Trudgill, the term originates from the Nordic language word "tittermatorter". A "teeter-totter" may also refer to a two-person swing on a swing seat, on which two children sit facing each other and the teeter-totter swings back and forth in a pendulum motion. Both "teeter-totter" (from "teeter", as in "to teeter on the edge") and "seesaw" (from the verb "saw") demonstrate the linguistic process called reduplication, where a word or syllable is doubled, often with a different vowel. Reduplication is typical of words that indicate repeated activity, such as riding up and down on a
Track gauge in North America South, moved them east and spiked them back in place. The new gauge was close enough that standard gauge equipment could run on it without problem. By June 1886, all major railroads in North America were using approximately the same gauge. The final conversion to true standard gauge took place gradually as track was maintained. Now, the only broad-gauge rail systems in the United States are isolated rapid transit, light rail, and streetcar systems as well as some heritage railways and hill railways. Track gauge in North America The vast majority of North American railroads are standard gauge (). Exceptions