A T rail is always attached directly to the underside of the ceiling.
For single suspension, the duct sliders slide into the bottom part of the rail. The sliders sit in a row at the top of the duct, at 12 o’clock. For double suspension, two rows of sliders slide into two rails. The sliders are attached to straps along the sides of the duct at 3 and 9 o’clock.
T rails are also used for suspending half-round (D-shaped) fabric dispersion systems. This is done using one of two methods: a bulb edge or sliders. Both types slide into the rails for easy duct removal.
