The American entry into World War I brought many changes to the Coast Artillery and CD Portsmouth. As the only component of the Army with heavy artillery experience and significant manpower, the Coast Artillery was chosen to operate almost all US-manned heavy and railway artillery in that war. Stateside garrisons were drawn down to provide experienced gun crews on the Western Front. Some weapons were removed from forts with the intent of getting US-made artillery into the fight. 8-inch, 10-inch, and 12-inch guns and 12-inch mortars were converted to railway artillery, while 5-inch and 6-inch guns became field guns on wheeled carriages. However, few railway artillery pieces were mounted and few or none saw action before the Armistice. The remounted 5-inch and 6-inch guns were sent to France, but their units did not complete training in time to see action. All three 10-inch guns from Fort Foster, both 8-inch guns from Fort Constitution, and both 6-inch guns from Fort Stark were removed; after the war the 10-inch guns were returned, but the 6-inch guns were stored and the 8-inch guns probably became railway artillery. At all the forts, numerous temporary buildings were constructed to accommodate the large influx of new recruits. Camp Langdon (named for the Revolutionary War hero and originally the New Military Reservation) was established in New Castle due to insufficient space at the forts. References indicate the authorized strength of CD Portsmouth was 10 companies, including four from the New Hampshire National Guard.