Confusion about which rail line is which has spurred transport planners to redesign Sydney's rail map to make it easier for passengers to understand.

Since a "T system" was introduced as part of an overhaul of the rail timetable in 2013, much of the misunderstanding when reading the map has been about the T1 line because it encompasses the Western, Northern and North Shore lines.

In an attempt to make it easier for commuters and tourists alike, the T1 Northern Line will be renamed the T9 Northern Line from April 28. As well, it will drop yellow for a distinct red, and extend from Hornsby to Gordon via Epping, and Sydney's central business district.

The redesigned map for Sydney's rail map includes the North West Metro (in aqua) and changes to the Northern Line (in red and renamed the T9). Credit:NSW government

The Metro North West line will also make its first appearance on Sydney's rail map in its trademark aqua – the same colour in which its driverless, single-deck trains are painted. The new $8 billion line from Rouse Hill in Sydney's north-west to Chatswood is due to open in May.