0-4-0 locomotives were built as tank locomotives as well as tender locomotives. The former were more common in Europe and the latter in the United States, except in the tightest of situations such as that of a shop switcher, where overall length was a concern. The earliest 0-4-0 locomotives were tender engines and appeared as early as c. 1802. The 0-4-0 tank engines were introduced in the early 1850s. The type was found to be so useful in many locations that they continued to be built for more than a century and existed until the end of the steam era.