Linux rides pillion on Mumbai city buses

In the swarming Indian metropolis Mumbai, it can be a gymnastic exercise just to fish in your pocket on the packed city buses and stretch out your paying hand to the conductor. Many commuters have opted instead for a ‘smart’ and cashless way to pay, provided, in part, by Linux. Named Go Mumbai, it is a prepaid smart card for BEST (Brihanmumbai Electric Supply and Transport) bus journeys.

In the most advanced configuration, two fare collection devices are mounted in the aisles near the front and back bus doors. These devices require the commuter to hold the smart card against them (contactless interface) upon entering and while leaving the bus. Each bus also has a control device. It uses a wireless LAN to talk with the fare collection devices, and, using GPS, tallies the distance travelled by individual commuters with the preconfigured route stored in its memory. The control device can be reprogrammed by the bus driver whenever the bus is rerouted. This triangle of devices in the bus uses ARM9 processors and runs embedded Linux using kernel 2.6. Having these Linux-embedded devices, says Satish Goriani, consultant to the technology provider Kaizen, drastically reduces the transaction time, and the inbuilt services in Linux, such as SSH, make it easy to manage them remotely. Forty buses are equipped in this way. The other 3,500 in the system use a more low-tech solution: a handheld device that the bus conductor uses to debit the smart card.

Riders can purchase Go Mumbai cards from 120 point of sale-and-refill PCs across Mumbai city at BEST’s bus depots and smaller outposts. These PCs run CentOS, a distribution compiled from the free packages used in Red Hat Enterprise Linux. Mumbai-based Kaizen Engineering Systems Private Limited, the administrator and provider of the system to the BEST, can remotely access the PCs using Secure Shell (SSH) for maintenance activities, thus ensuring their reliability and uptime. By contrast, Goriani says, “Telnet (remote) access on Windows is prone to attacks. SSH is more secure.” At present, the point of sale PCs have sold 800,000 smart cards in Mumbai.

From the point of sale terminals, the fare collections are digitally transferred to individual float accounts on back office servers running Sun’s Solaris operating system. When the rider uses the card, the float accounts are debited accordingly. The system handles transactions daily worth Indian rupees (inr) 2.5 to 3 million citywide.

Deployed in January 2007, the system is so stable that it will this month be officially extended to part of Mumbai’s suburban railways as well. It is also secure, and has had no hacks and cracks, according to Kaizen.

Thanks to the system’s use of Linux, BEST saved about inr 1.2 million on the point of sale infrastructure alone, as compared with a Microsoft Windows setup, Goriani says. BEST paid nothing for the rest of the system, signing instead a revenue-sharing contract with Kaizen.

Though the first of its kind in India, the smart card system needed no radical development; it used off-the-shelf embedded Linux hardware and existing solutions modified for Indian currency rates and for physical considerations such as Mumbai’s clammy climate and the rigors of bumpy journeys. Its supplier, Australia-based ERG, has provided a similar solution to Singapore’s public transit system.

The BEST system has had a very low failure rate, not least because of the reliability offered by Linux at the points of sale and onboard fare collection, Kaizen has found. Of the 450 embedded Linux fare collection devices deployed in a recent pilot with the railways subsequent to the success with the bus service, only four units crashed — all due to hardware or electricity failure. “The OS failure is insignificant,” Goriani says.

The BEST system is yet another example of how Linux is making inroads in all kinds of niches, thanks to its low cost and high reliability.