NML:Railtypetable-Roadtypetable-Tramtypetable

railtypetable {
	ITEM [, ITEM]*
}

Each ITEM can be either a 4-byte long Identifier or string or it can have this format:

ID : [ ID[, ID]* ]

The first ID is the name (doesn't have to be 4-bytes long), the other iDs are a list of labels that are assigned to the given name if they are available.

 railtypetable {
 	RAIL,
 	ELRL,
 	"3RDR",
 	RT_SHINY_RAIL: [SHNY, RAIL]
 }

The label 3RDR is written as a string because an identifier can't start with a numeric value. To reference it later you can write railtype("3RDR"). If another grf defines a railtype with label SHNY then RT_SHINY_RAIL will refer to that track type. If the railtype SHNY is not available then trains using RT_SHINY_RAIL as track type will fallback to RAIL.