The Mashair Railway, also known as Mecca Metro, rolls out on Sunday to serve pilgrims beginning the annual hajj rituals near the Muslim holy city, bringing a new solution to crowding.
The dual-track light railway, with its initial number of nine stations, connects the three holy sites of Mina, Muzdalifah and Mount Arafat -- areas that see massive congestion during the five-day pilgrimage.
It will replace 4,000 buses previously used.
The first official trip will set off from Mina at 8:00 pm (1700 GMT), as pilgrims gather there, outside Mecca on the Tarwiah Day to prepare for the peak day of Arafat, when some 2.5 million are expected to gather on Mount Arafat and its surrounding plain.
The Chinese-built railway, only to be used for five days a year now, will only operate at 35 percent of its full final capacity in the first phase.
It will be open only to Saudi and Gulf pilgrims, forecast at some 130,000 Saudis, 10,000 Kuwaitis and 10,000 Bahrainis, said Saeed al-Qurashi, head of the Hajj and Umra Committee at the Mecca Chamber of Commerce.
The number is modest in comparison with the total number of pilgrims, but other nationalities will be able to use the train in the second phase.
While all pilgrims begin the journey in Mecca, the train initially will run only from Mina, to the east, and on to Muzdalifah and Mount Arafat further east.
All pilgrims leave Mina for Arafat by the 9th of the Dhul Hijja month of the Muslim lunar calendar, which is Monday this year.
Later Monday they all descend by train back to Muzdalifah, halfway between Arafat and Mina, and Tuesday they all head back to Mina, where they stay up to three nights.
The railway will eventually stretch the extra few kilometres to Mecca, home of the Muslim holiest shrine.
At Arafat 1 station, the light-green train pulled in during one of the trial runs conducted to test its readiness. Chinese workers were seen still working to fix a ventilation system on the 10-metre- (33 feet) wide marble platform.
"The platform has a capacity to accommodate 3,000 passengers at a time," said Yasser al-Sibaei, a Saudi supervisor at the station.
He said the plan is to get 3,000 passengers into the train, and then bring the same number onto the platform for the next journey.
Platforms are protected by glass barriers whose doors open simultaneously with the train doors to ensure the security of waiting passengers.
The elevated stations also have wide ramps for pilgrims to flow out smoothly, backed by lifts that can carry up to 50 persons at a time.
Most of the station agents appear to be Egyptian and Saudis. Egyptians with experience in running the metro of Cairo were recruited to operate the control rooms.
"It is an honour to serve the pilgrims and represent our country," said Saber Bernawi, a Saudi agent said.
Mansur al-Blushi, a Meccan who is at university in South Africa said he took up the seasonal work to make some pocket money.
"I study abroad. It is a chance to come to see my family and make some pocket money," he told AFP. Station agents are paid 5,000 riyals (1,333 dollars/970 euros) for the two-week contract.
British Serco service firm has been contracted to provide operations and maintenance consultancy, in cooperation with China Railway Construction Corp (CRCC).
The 1.8-billion-dollar project is the first of two rail links aimed at easing pilgrim traffic. The much larger Haramain High Speed Rail is set to stretch 444 kilometres (275 miles) between Mecca and Medina, the second Muslim holy site.
Local Al-Rajhi construction group together with France's Alstom and China Railway Engineering won the first-phase of the 6.8-billion-riyal (1.8-billion-dollar) contract for civil works.
The train which will travel through the Red Sea city of Jeddah is planned to run at a high speed reaching 360 kilometres (225 miles) per hour and ease traffic of pilgrims between the two sites.
Explore further: Accessibility expert confronting double-edged sword of technology