NML:Item

item (<expression> [, <ID> [, <expression>]]) {
	(<property-block>|<graphics-block>|<livery_override-block>)+
}

The first argument is the feature of the item, the second (optional) argument is the name used to identify the object throughout the NML file and the third (optional) argument is the numerical id you want to use for this item. Example:

 item (FEAT_ROADVEHS, hereford_tram) {
 	property {
 		name:               string(STR_NAME_HEREFORD_TRAM);
 		climates_available: ALL_CLIMATES;
 		introduction_date:  date(1940,1,1);
 		speed:              60 km/h;
 	}
 }