Putting down more track is the most reliable way of providing for the running of more trains and reducing delays.

• Two parallel tracks means trains running in opposite directions don't have to wait for each other.
• Three parallel tracks means express services can overtake stopping services in one direction, which is good for peak time but not very useful off peak.
• Four parallel tracks means express services can overtake stopping services in both directions, which is useful at any time.

Obviously four tracks is the most desirable arrangement, but it also costs the most to provide.

In Melbourne today, where service levels are adequate for off-peak but more capacity is required for peak time, triplication is a valuable upgrade.

However, many Melbournians value overall journey time very highly, which makes the provision of all-day express services a priority in any attempt to attract serious amounts of patronage onto public transport. Allowance should be made for four parallel tracks whenever major works are being carried out - for example, when bridges over railways are being built there should be space for four tracks underneath. Also any reservations for new lines should be wide enough to take four tracks.