Monday, December 27, 2010

Route 837's clever weekday timetable

A previous look at the new Casey-Cardinia bus network (which started last week) indicated that the new timetables improved local route coverage and span more than train connectivity, often because of incompatible bus and train headways (table below).

Cautious passengers in Casey/Cardinia should assume non-connectivity unless otherwise known, especially on weekends.

However one still sometimes finds exquisite examples of good planned connectivity. These are even more remarkable given the difficulties of planning buses around trains every 30 to 40 minutes (compared to 15 - 20 minutes on other Metro lines).

A good example is the weekday timetable for Route 837 between Berwick Station and Beaconsfield East.

Train times

Let's start by checking the area's train times.

Off-peak weekday trains to the city from Pakenham leave Berwick at :20 and :50 past the hour.

Going the other way, off-peak weekday trains from the city to Pakenham leave Berwick at :01 and :31.

Trip generators and passenger flows

Route 837's main trip generators are clustered at the Berwick end of the route. They mostly either in the main street or near the station. Hence peak passenger flow would be towards Berwick in the morning and away from Berwick in the afternoon/evening. This peak flow is only amplified by the route's service of Berwick Station, with a similar peak flow, but this time towards the City and Dandenong in the morning and away in the afternoon.

Analysis

Let's see how Route 837 meets these travel needs, especially train connectivity.

The route runs hourly on weekdays, so could potentially meet every second train if well planned.

And it does. In the morning off-peak Route 837 arrives at Berwick Station at :45. This allows a five minute connection to the train leaving at :50, which is near-optimum.

A closer look at the 837 timetable indicates that the hour spacing does not apply throughout the day. Most notable is the 75 minute gap around noon (arrivals at Berwick are 9:45, 10:45, 11:45, 13:00, 14:00, 15:00, 16:00 etc).

It's similar leaving Berwick; in this case departures to Beaconsfield East are at 8:56, 9:50, 10:55, 12:06, 13:06, 14:06, 15:06 etc.

This initially looks bad; it's not a pure clockface or memory timetable, which lessens legibility.

However let's review train connections before rushing to judgement.

The morning train connections so praised in the to city direction aren't as good the other way. For instance, the ex-City train that meets the 10:55 bus arrives Berwick at 10:31am. This is a 24 minute wait. 24 minutes is nearly as long as the entire bus trip and is high compared to the train's 30 minute frequency.

But look at what happens in the afternoon, when the altered midday spacing puts the bus departures at :06 for afternoon off-peak trips towards Beaconsfield East. With train arrivals at :01 the connection time is once again down to a near-optimum five minutes. This time, in the afternoon, it's the trips towards the city that are not so well connected.

Timetabling always involves trade-offs. It is unlikely that good connections will be consistently possible in all directions, although exceptions can exist where trains cross.

Nevertheless it is possible to select which interchange points and travel directions are most important and schedule buses accordingly. The bad connections don't go away, but they do mean that most passengers most of the time do not encounter them. And given the low train frequency, it is more important to have a bus timetable that connects than one with a perfect clockface schedule but just misses connections.

Conclusion

To conclude, Route 837's good bus/train connectivity in both weekday am and pm dominant directions is precisely the sort of good service planning that we need more of. It is made even more praiseworthy by the area's lesser train frequencies that makes the job harder yet more important for the services in the area to function as a genuine network.

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1 Comments:

Blogger Damo said...

I'm glad you've had the time to look into this in detail, because yes, you are quite correct. It is a shame that other outer suburban areas on such frequencies have not had the same treatment.

8:14 pm  

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