A transport unit, such as a container, a railway carriage, a truck or a trailer of a vehicle combination, and a movable loading platform, the transport unit comprising a loading base (7, 7', 7", 7"') for supporting a load (6, 6', 6", 6"') from below in a vertical direction in the transport unit and a support arrangement for supporting the load in a horizontal direction in the transport unit, the support arrangement comprising at least one support column (8a to 8f, 8a', 8b', 8a", 8b", 8d", 8f", 8a"', 8b"', 8d"', 8f"') whose bottom end is arranged to be supported by the bottom (1, 1', 1", 1"') of the transport unit and whose side is to be set against the load (6, 6', 6", 6"') to be supported, the loading base (7, 7', 7", 7"') of the transport unit comprising a set of locking recesses (9, 9', 9", 9"') for receiving bottom ends of support columns (8a to 8f, 8a', 8b', 8a", 8b", 8d", 8f", 8a"', 8b"', 8d"', 8f"') and for fastening the support columns in a detachable manner to the loading base, the locking recesses (9, 9', 9", 9"') being arranged in the bottom (1, 1', 1", 1"') of the transport unit in at least one line parallel with the longitudinal axis of the transport unit and, in addition, in a plural number of parallel lines (L1, L2, M1, M2, M3, M4) that are transverse to the longitudinal axis of the transport unit, the locking recesses (9, 9', 9", 9"') comprising fastening means (10, 10', 10", 10"') arranged to lock the support columns and a fastening member (11a to 11f, 11a', 11b', 11a", 11b", 11f", 11a"', 11b"', 11f"') at the bottom end of the support columns so that when the fastening member is in a locked position in relation to the fastening means, lifting of the support column from the locking recess is prevented, and the locking recesses being arranged to enable the fastening member of the support column to be released from the fastening means and the support column to be lifted from the locking recess, when the fastening member is in a released position in relation to the fastening means, the transport unit comprising tightening means for tightening the support column (8a to 8f, 8a', 8b', 8a", 8b", 8d", 8f", 8a"', 8b"', 8d"', 8f") against the load (6, 6', 6", 6"'), the tightening means comprising an elongated flexible member (16a to 16f, 16a', 16b', 16a", 16b"', 16d"', 16f"', 16a"', 16b"', 16d"', 16f"') and a tightening device (17a to 17f, 17a', 17b', 17a", 17b", 17d", 17f", 17a"', 17b"', 17d"', 17f") for tightening the elongated flexible member, a first fastening end of the tightening means being fastened to the transport unit and a second end of the tightening means, which is opposite to the first fatening end being fastened to a top end of the support column, characterized in that the fastening member of the support columns being locked to the fastening means of the locking recesses in the locked position so that the support column is able to tilt towards the load, and the tightening means being arranged to tilt the support column and change the angle (α) thereof in relation to the loading base (7, 7', 7", 7"') so that the top part of the support column presses against the load (6, 6', 6", 6"') when the elongated flexible member is tightened with the tightening device.