Sunday, June 14, 2009

What is a 'connecting service'?

The back of Melbourne train timetable booklets have a handy section on 'connecting' buses. This lists bus routes departing from each station and their destinations. This and Human Transit's post on transfers led me to ponder what qualifies as a connecting service.

At least in Melbourne, the term 'connecting service' is used loosely and devalues the term's potential meaning to passengers. It could be anything from an infrequent bus that departs from a busy road across from the station to a cross-platform transfer to a waiting train. In my view a genuine 'connecting service' imposes two main requirements; one physical access and the other temporal.

The access requirement means being able to get to the stop of the service that you are transferring to. If you can then the services can be described as 'intersecting'. Melbourne does this quite well; apart from a couple of cases (eg Southland and Campbellfield) if your bus goes near a railway you can be fairly sure there will be a station to change to not far away.

The time requirement is less definite and a judgement may have to be made, depending on mode and context. A 28 minute 'connection' is too short to be reliable at an international airport but is excessive for a suburban train-bus connection. However it might be just right for a connection between interurban trains at Southern Cross.

The best scheduled connections involve a bus for every train (eg 571 and 896 TrainLink services). This implies buses departing at the train service frequency ie harmonised headways. Acceptable compromises for local routes may include shorter operating hours for buses and their frequency being set to meet only every second train. However headways must first be harmonised (a bus every 30 minutes cannot reliably connect with a train every 20 minutes so does not qualify) with departures tweaked to minimise waiting. If it meets these requirements, I would describe the bus as 'connecting'.

Then there is what happens if the train is late. Are connecting services held for the train? And if so, is there a cut off time when the bus departs even if the train has not arrived, since buses have their own schedules and passengers to serve? If the answer to the first question is yes, and the policies on the second question are conveyed to passengers, then this could be defined as a 'guaranteed connection', although the guarantee could be described either as 'conditional' or 'absolute'. In Melbourne off-peak Alamein and Williamstown lines offer guaranteed connections as most of their passengers will be arriving on ex-city trains that continue to Ringwood or Werribee. A similar arrangement applies for tram routes 5 and 64 at some times of the day and probably country coaches (especially those that substitute for closed country branch lines).

To recap, there are three levels of service connectivity.

* The first is 'intersecting services', where passengers can transfer between services but no warranty can be given regarding reasonable waiting times or even if the service is still running. This applies to most buses listed as 'connecting' in the back of the train timetable.

* Secondly are the services that connect with short and predictable waiting times if both are to schedule. These require either frequent service or harmonised headways and can be regarded as genuine 'connecting services'.

* Thirdly is the highest and best level of connection, where services are held if there is late running. These are 'guaranteed connections', though the guarantee can either be 'conditional' or 'absolute'.

It would help if we used the correct term for what we mean to describe the relationship between a railway line and a passing bus route. Then terms like 'connecting service' get a firm meaning, and can become a selling point, much like Adelaide has achieved with 'Go Zone' and we have partially achieved with 'SmartBus'.


Jarrett at said...

Bravo. Very important distinctions. Will follow up soon.

Vic Rail (Riccardo) said...

Did you see Nathan Rees promising bus train connections?

Daniel said...

Melbourne's traditional jargon for what you (and most others) think of as "connecting" (physical and temporal proximity) is "co-ordinated"... and is, as you imply, relatively rare.

Peter Parker said...

Ricc - I thought I saw something during the week, but I don't know how he intended to do it unless he had a magical ability to withhold funding from any bus route that didn't connect.

In the case of Werribee he might have been thinking of improving connections through the almost TUAG weekday train service.

However Werribee is one place where, through the right person in the right job at the right time, existing bus timetables already show exceptional connectivity.