Abstract: A trailer having a tiltable main deck and a shiftable undercarriage includes an undercarriage assembly having a deck support structure mounted thereon for supporting the deck. The deck support structure includes lifting arms for lifting the elongated deck assembly relative to the undercarriage independently of the undercarriage shifting mechanism so that the deck may be lifted relative to the undercarriage without simultaneouly shifting the undercarriage along the deck. The trailer may include a hitch assembly that permits the trailer to be pivotally connected to a towing vehicle to permit the forward deck to be tilted away from the main deck to increase the angle between the main deck and the forward deck when the trailer is in the unloading position. Further, a deck angle adjustment assembly is disclosed for adjusting the relative positions of the decks.