[RightWhale]

Interesting. Did the Americans have such facilities?

[Grimmy]

Others with better learning and understanding may answer differently, but from my limited knowledge, no.

The US forces went into action just as the German forces were nearing Paris and the allied armies were nearing collapse. US forces were used primarily to halt the German advance and then in the counter attacks that followed.

Our forces weren’t in static positions long enough to have developed such extensive systems of fortification.

[Toliy]

From what I've read about American participation in WWI, they did not construct such intricate defensive works. There were a couple reasons:

1) The Americans were not in the line long enough at one place to warrant creating a network of this complexity (the British were at Ypres for 4 years!). For example, the famous Belleau Wood Operation was the assault and defense of Chateau-Thierry and the Wood by the 2nd and 3rd US divisions, which had no time to fortify at all.

2) The American strategic and tactical doctrine dictated an offensive spirit for each division. The Soissons Operation in April-July 1918 showed this clearly: regimental, brigade, and divisional commanders were more likely to advance than wait for their neighbors (this frustrated the French, who preferred to advance as a corps, where each regiment and division was tasked with reaching subsequent objectives and establishing contact with neighbors). At Argonne, the Ameircans went into line at the start of the big push in the summer of 1918: again, no need to dig under ground.

Incidentally, when the American 132nd regiment was deployed with the Australian 4th Division at Le Hamel (July 1918), the offensive spirit of the Americans was reinforced (and sharpened) by the experienced Australians.

[Ironclad]

My great uncle fought in Flanders in the 91st Division, October - November 1918. I have his diary. They unloaded, formed up, and went right into action - no trench warfare. He doesn’t mention tunnels.