Hi. When I was gathering informations about the US attack on Guam 1944 I found the OOB for the 1st Provisional Marines Brigade. It mentions a pioneer and an engineer unit in every Regimental Combat Team. What´s the difference between those types of units? Yours tom!
As far as I understand it, Pioneers are specialised assault infantry trained in flamethrowers, demolition charges, etc. Engineers are more well, Engineers, they are trained in demolition but are also capable at constructing field fortifications, defences, clearing enemy defences, bridgebuilding, etc. One can be thought of as infantry with some engineering training, the other Engineers with some infantry training.
In the US Marines Pionner battalions were primarily logistical support troops and formed the bulk of the shore parties, that is moving supplies and equipment across the beaches to the fighting troops. They would also be used to provide manpower for constuction jobs, and, like all Marines, they were trained to fight as infantry in a pinch. Marine Engineer battalions were combat troops, equipped and trained to use specialized weapons such as flame throwers and demolitions and to provide additional mobility through construction of roads, bridges and trails. After Tarawa all Marines were trained in the use of "engineering" combat weapons such as flame throwers. US Navy Construction Battalions (CB or SeaBees) were originaly part of the Marine division organization and together with the Pioneers and Engineers formed the divisional Engineering Regiment. By 1944 the Engineer Regiment level was removed when CBs were withdrawn from the official marine division organization and assigned as Corps troops, although they were still frequently attached to a division.
