Review of the AC Overhead Wires, the DC Third Rail and the DC Fourth Rail Transit Lines: Issues and Challenges

Abstract

This paper focuses on transits available around the world. AC voltage transits and DC voltage transit are reviewed and compared. Emphasis is given to differences, advantages and disadvantages of voltage supplies and traction types. First, differences between bus rapid transit (BRT), metro, light rail transit (LRT) and light metro are covered, with special attention to statistical of annual passengers per year, an attribute that defines the type of railway transit. Mention is also made to the history of DC and AC overhead wires, other traction preferences for metro transit and highlighted differences between the third rail and fourth rail traction. Malaysian transit systems are then discussed, with special attention to LRT Kelana Jaya line, world"s third DC transit that employs the fourth rail traction. The discussion have produced relevant statistical data that this paper is in part aimed at summarizing and at comparing with what accomplished on the same subject within the third rail traction framework. The increased in LRT Kelana Jaya line annual passengers per year is a proof of success for the fourth rail technology.

Electrical Performance of Polymer-Insulated Rail Brackets of DC Transit Subjected to Lightning Induced Overvoltage

“…Boasted as the busiest light rail transit in Malaysia with 46.4 km line length, the LRT Kelana Jaya line runs seamlessly between the north eastern suburbs of Kuala Lumpur to Petaling Jaya and west of Kuala Lumpur with 37 stations [1]. This electric transit train runs on a 750 VDC fourth rail system and has been operating for two decades.…”

“…A fourth rail traction technology came into the picture as a post development of the third rail traction technology. The main advantage of the fourth rail traction is that the running rails would not have to carry either polarity of current, thus avoiding the stray current issue which can lead to corrosion and even arcing, especially if the tunnel segments are not electrically bonded [1]. For instance, in the case of London Underground, which runs through Victorian mains that predated the railway section, where the pipe segments were never constructed to serve that purpose [2].…”

“…London Underground is one of the three urban transits in the world that employs the fourth rail traction technology. The other two are Milan Metro Line 1 and the Light Rail Transit (LRT) Kelana Jaya Line in Italy and Malaysia, respectively [1,2]. The LRT Kelana Jaya line is distinguished by not only running underground but being the only one that partially runs on the elevated track.…”

Sizing Algorithm for a Photovoltaic System along an Urban Railway Network towards Net Zero Emission

“…Railway Electrification Systems. Electric trains are comparatively more efficient than fossil fuel trains [1,2]. Thus, the integration of electric trains throughout the globe is still increasing.…”

“…Existing transportation methods include public vehicles such as buses; personal vehicles such as cars, vans, and bikes; and rail transportation. Rail transportation is more attractive to the public, as it is more convenient than other methods [1]. Electric railway systems are beneficial due to lower power consumption and greenhouse gas emissions compared to traditional fossil fuel-based railway systems [2][3][4][5].…”