7 aspects of understanding the Metro Rail-Train Operation Plan.
Discover the effort that goes into building an engineering marvel.
Metro, the most integrated means of transportation, often goes unappreciated and how it functions is still a mystery for a lot of people. The entire system is developed to relieve the severe stress on the cities and excessive pressure on its transport system. A meaningful and sustainable mass transit system hence becomes necessary to ensure proper transportation facilities are available for the people.
Through this series of articles, I would like to help you develop a sense of understanding of the general functioning and technicalities of a metro rail system.
Being an electrical engineer, I can help you understand the various technical and functional aspects of a metro. The primary electrical engineering components in a metro system include the rolling stock requirement, train operational plan, traction system, signaling & transmission system, substations & power supply, ventilation/air conditioning, and maintenance depot.
These are the seven electrical engineering aspects of Metro railways. In MRTS (metro rail transit system), all the above-defined operation is in electromechanical integration. In this article, we will explore the second aspect of metro railways, the Train operation plan.
The underlying operation philosophy is to provide suburban services at an economical cost, with fixed infrastructure and Rolling Stock Planning here basic needs and requirements of the mass transit system is mentioned-
- Selecting optimum Train frequency to provide sectional capacity commensurate with the peak direction traffic demand during peak hours.
- A minimum frequency of train service during the lean period so as to make this service attractive during the lean period also in comparison to other options.
In order to get a reasonable estimate of traffic that will use our metro, we need to do surveys to find out the direction of maximum traffic in the city. We also need to get a reasonable estimate of the traffic in the stations at each location. One feature of metro station locations that arise when looking at them from a system point of view is that most are planned on the basis that passengers are prepared to use metro services if it’s within their convenience (less than 1000m), any further and they tend to find alternative transport or use another route. This drives station spacing between 1000 and 1200 meters.
Once the traffic demand has been determined, the next jobs are to:
- Set out route and stations;
- Calculate train service frequency & the number of trains required;
- Draft the timetable;
- Prepare rolling stock;
- Determine the fare structure;
- Set up the managing operating structure.
Steps To Plan A Metro System:-
- Metro Route Plan- First we plan out the metro route using the public
transport density study. - PHPDT Value Calculation- Once the route is planned the next step is to calculate the value of the peak hour peak direction traffic using statistical methods and population density analysis.
- Train Round Trip Time Calculation- It’s defined as the time
required by the train to complete one trip on the entire route and come back to its initial starting position. Calculation of trains round trip time by estimating a provision time for allowing change of crew, change of train routes (as in scissor terminals Central, Hong Kong MTR), in terminals stops.
Let the calculated round trip time be (T round trip). - Train Headway Calculation- The time interval required between
consecutive trains to operate a PHPDT condition is defined as headway generally expressed in minutes.
We first set our crush capacity of train coaches and then divide the PHPDT value with that of the train's crush load value giving us the number of trains required in one hour, which is generally expressed in minutes or seconds. Practically achievable headway is 2.5 minutes as practiced in Delhi Metro(India).
We consider- 3 people/sqm as a normal condition, 6 people/sqm as crush condition, 8 people/sqm as dense crush condition. let the calculated headway time be (T headway).
5. Number Of Trains Required- Once the headway has been evaluated, we calculate the number of trains we actually require to operate in this condition, which is given by the round-trip time divided by the headway time.
N (number of trains required) = (T round trip)/ (T headway).
Additional Spares
Spare trains are bought along with the required ones to give provision for repair and maintenance of trains in depot and inspection lines.
Once the number of trains required is found out the final step is to plan out the maintenance depot and calculate the stabling lines required with provision for the spare line.
Conclusion-
Metro, in itself, is a very vast aspect of engineering and is integrated into our lives. I can’t emphasize enough on its importance in the development of a nation and its functionality in supporting traffic flow.
From the article, I tried to give you a clear image of what kind of thought process goes through in creating such an engineering marvel, so next time you board a metro, don’t forget to appreciate the effort that goes into developing one. Make sure to check out other parts of the series to get a full understanding of the functioning of a metro.
