Military craftsman personnel in ME

[Hisoka Morrow]

Everything about military craftsman personnel management are welcomed to left, such as during the battle of Black-Gate during War Of The Ring, why the craftsman personnel mentioned in charge of transport roads maintaince yet not appearing in the war-zone of Black-Gate for fortification by JRRT,or Maeglin and his house of mole get adapted into Turgon's expedition during the Unnumbered Tears as logistic personnel, and so on. Why there're no craftsman personnel during the battle of Black-Gate in 1944 for field fortification against the Wain-riders? Don't forget it's obvious at least the Wain-riders obviously prefer field tactics than siege.
Yeah, any thought?