The vehicle pictures comprising the trains should be entered generally in the direction they travel and separated from each other by a comma.  The following symbols can modify the composition of a train or a train part or the individual vehicles that comprise them when they are used as <GlobalModifier>  :

< Regardless of the direction of travel or the definition direction outside the parentheses/macro, the pictures always appear from left to right.
> Regardless of the direction of travel or the definition direction outside the parenthesys/macro, the pictures always appear from right to left.  

This is particularly useful for trains that must have a fixed sequence of vehicles, independent of the direction of travel such as push-pull trains or EMUs/DMUs.

Using the direction modifiers inside a parenthetical statements causes them to act only on the content of the parentheses - so you can fix the sequence of only a part of the train, leaving the other part depending on the running direction.

Example:

    (<DMU_LEFT_PART,DMU_RIGHT_PART),TRAILER

will generate the DMU from two parts always in the fixed left-right order, but the trailer will always follow the DMU regardless of the running direction.