A clock-face schedule is a timetable where public means of transport run in consistent intervals, and as an extension programs lines to converge on hubs at a given point of the clock-face. A clock-face schedule is used in the New York City subway system, the London Underground, Merseyrail Northern and Wirral lines, and metropolitan transit. Its name comes from the fact that departures take place when the minute hand is at the same place every hour (e.g. 6:15, 7:15, 8:15, etc.)
The goal of clock-face schedules is to increase the attractiveness and versatility of public transport. They are easier to memorize for passengers, because departure times repeat. A constant schedule over the whole day can also improve service during off-peak hours. They can be attractive for transportation companies, because the repeating pattern makes more efficient use of personnel, infrastructure, and vehicles, and can make resource planning easier.
The opposite of a clock-face schedule is a timetable that is purely driven by demand, with irregular headways.
Each line can have an individual regular schedule, without connections to other lines. Even in this case it may be necessary to coordinate different means of transport if the mode of transport changes, for example at the terminal stop of a tram network, if the line continues by bus. This may, however, cause passengers to have to wait at the transfer point for any number of minutes until the next bus or train comes along.
These timetables may be attractive even if they don't provide connections to other public transport, because they allow a continuous use of vehicles and personnel.
Line-bound regular timetables are especially useful for lines with high service frequencies. If vehicles with the same destination follow each other in short intervals, transfer times are short even with delays. However, if the service intervals are 20 minutes or longer, lines usually should be coordinated. One simple way of doing this is to shift the departure times of one of the lines to match the other.
An integrated schedule is a clock-face schedule that covers not just some lines, but the whole area served by possibly several different means of public transport. A characteristic of integrated regular timetables is that there is more than one central hub, instead it applies the hub concept to the whole transport network.
Having several lines meet at hubs with vehicles of all lines arriving and leaving at the same time is a modern way of connecting multiple lines. Usually, all lines wait for a delayed vehicle. The goal is to reduce transfer times to a few minutes, with a default time of five minutes. However, in actual operation this time span is often larger due to vehicles being early or late, high passenger volume (e.g. rush hour) or assisting passengers with disabilities. Due to the waiting times at such transfer stops the through service on a line can become unattractive and cause the rest of the lines to be late for the next loop.
Examples of such networks are often nighttime and city bus networks. The connections are only optimized within the network, but not for transfers to rail or intercity bus lines. Such concepts need purpose-built stations which can handle high passenger volumes. The space constraints within cities can be a reason to seek other concepts.
An integrated regular timetable needs routes that take 28 or 58 minutes, in order for a vehicle to make it from one hub to another in time. In contrast, a route that takes 40 minutes would be bad, because vehicles and possibly passengers would have to wait uselessly for their connections. Thus, a route that takes 40 minutes generates nearly the same cost as a route that takes 58 minutes, because vehicles and personnel can't be used in the remaining 20 minutes. Therefore, lines are often cut or extended to meet this requirement when an integrated timetable is introduced.
Emergence of integrated timetables
The first integrated regular timetables were developed for railways. After the successful introduction of a line-bound regular timetable on one line in Switzerland in 1968, the development continued in the Netherlands. In 1970/71 Nederlandse Spoorwegen introduced a regular timetable with multiple hubs. In Germany, the first large-scale use of regular timetables was the InterCity network of 1979, which provided hourly long-distance services between cities. In 1982, a nation-wide integrated regular timetable was introduced in Switzerland, which covered all but a few railway and bus lines. The base frequency was once an hour. The system was improved every two years, and resulted in the Rail 2000 project of Swiss Federal Railways.
Services on the Swiss railway network are integrated with each other and with other forms of public transport. Unlike its European neighbors, Switzerland has not developed a comprehensive high-speed rail network, with the running speed on its one stretch of relatively high-speed line being 160 km/h. Instead the priority is not so much the speeding up of trains between cities, but the reduction of connection times through the nodal system. Swiss Federal Railways have adapted their infrastructure in such a way that journey times on main lines between hubs are multiples of 30 minutes so that on the hour or half-hour all trains stand in the main stations at the same time, thus minimising connection times. Indeed the above-mentioned Rothrist-Mattstetten line reduces journey times from Bern to Zurich from 72 minutes to 57 minutes, in keeping with the clock face scheduling.
However, on some single tracked lines the published timetables may be 30/30 or 60/60 minutes, while the actual timetables are slightly asymmetrical, because the passing loops are not positioned ideally.
Since 1990, most States of Germany have introduced integrated timetables for short-distance public transport, running hourly or every two hours, e.g. Allgäu-Schwaben-Takt in 1993, Rheinland-Pfalz-Takt in 1994 and NRW-Takt in 1998. Transport associations have introduced regular timetables with base frequencies of 20 or 30 minutes, which are partially intensified to 10 or 5 resp. 15 or 7.5 minutes by overlaying multiple lines. In some areas, local buses are also integrated, e.g. RegioTakt in NRW and in parts of Lower Saxony.
These developments have led to "integrated timetable islands", which all do adhere to the Germany-wide symmetry minute (58½), which is used also in Switzerland and partially in other European Countries. Major problems exist in regions where transport associations of different states interact (e.g. at Osnabrück). In order to introduce a Germany-wide integrated regular timetable, the alliance "Deutschland-Takt" was founded in 2008. Its goal is to start a discussion about a better system for public transport in Germany and to highlight room for improvement. The Bundesarbeitsgemeinschaft Schienenpersonennahverkehr (BAG-SPNV) together with Deutsche Bahn AG are currently conducting feasibility studies for a Germany-wide integrated timetable.
- http://web.archive.org/web/20080306143156/http://ned.gschieder.ch/download/bahn/bahn.htm Section „vertakten“ (German)
- Called the Rothrist-Mattstetten line
- p3. http://www.osaka-sandai.ac.jp/ce/rt/19xx/07/WCTR-070501j.pdf
- p.29 http://upcommons.upc.edu/pfc/bitstream/2099.1/13979/1/LEARNING%20FROM%20SWISS%20TRANSPORT%20POLICY_Lydia%20Alonso.pdf
- Deutscher Bundestag (Hrsg.): Antwort der Bundesregierung auf die Kleine Anfrage der Abgeordneten Dr. Anton Hofreiter, Winfried Hermann, Bettina Herlitzius, weiterer Abgeordneter und der Fraktion BÜNDNIS 90/DIE GRÜNEN – Drucksache 17/2258 – Untersuchungen zur Liberalisierung des Fernlinienbusverkehrs und seinen Auswirkungen auf den Schienenpersonenfernverkehr. Drucksache 17/2535 vom 8. Juli 2010 (German)
- Integrated timed transfer
- Integrated timetable of the Zurich S-Bahn - The numbers are minutes, timetable repeats every hour