Based on current figures Melbourne Airport would only require at most 4 trains per hour (each way). Airport passenger arrivals and departures are intermingled these days, ie the peak is in both directions.
- 8 x 800-passenger trains per hour = 6400 passengers per hour
- Allowing for a 60/40 imbalance between arrivals and departures still gives a capacity of about 5300 per hour.
- For the train to capture 25% of the total airport passengers, there would need to be more than 20,000 airline passengers per hour (4 x 5300 = 21,200).
- To achieve 20,000 per hour would require 100 takeoffs and landings per hour at an average load of 200 passengers per plane.
Brisbane’s Airtrain has 15-min headways in peak and 30-min in off-peak. Melbourne Airport’s justification is based on projected figures for the mid 2030s. Hindsight phrases such as ‘patronage less than expected’ come to mind.
Calendar year 2018: 25.8m domestic and 11.4m international passengers went through the terminals.
Simply divided by 365 days in the year thats just over 100k passengers a day. In reality weekdays would skew slightly higher and weekends would skew slightly lower (except natural peaks like Sunday afternoon/evening).
Rough peak domestic times: 6am-10am (departures) 7am-11am (arrivals) and 4pm-8pm (departures) and 5pm-9pm (arrivals).
Rough peak international times: 6am-10am (arrivals) 8am-11am (departures), 3pm-7pm (departures), 9pm-midnight (arrivals), 10pm-1am (departures).
Airline staff (whether kerbside or airside) shifts generally start from 4am and are staggered throughout the day (flight crew who are on 9am departures don't turn up for work at 4am!). Other staff (Border Force, AQIS, retail outlets, Airport management etc) would be similar but probably don't have the same shift spread.
If it's 37.2 million passengers now, using a conservative annual patronage growth rate of 3% (in the past 10 years we've seen peaks double that) by the time a MARL might open (gov says 2027 - 8 years away) there will probably be ~45 million passengers a year or 123k per day (again using a simply annual divide 365 calc).
If I were to gaze in a Crystal ball - Weekdays 6am-9pm: 6TPH/10 minute frequencies. Perhaps 15 or 20 minute frequencies starting from first service around 4:30 until 6am and same from 9pm until a last service around midnight. Weekends same core 6TPH/10 minute frequencies but probably start 7am or 8am until 8pm or 9pm (except for Sunday nights which is one the busiest times for domestic aviation).
If they're going to be really picky trying to match capacity to the aviation peaks they might pull the frequency back from 10min to 15 min from for 3-4 hours in the middle of each day.
And that assumes an 800 capacity trains, if they're smaller, it'll be higher. Regardless, here's hoping MARL and SRL is an automated system so capacity can quickly be added when and where it's needed rather than waiting for 6+ month timetable changes.