From The Arab Awakening, George Antonius, G P Putnam's Sons, 1946. 

Its main line was constructed between 1900–08, and inaugurated in September 1908. It traversed 820 miles (1,320 km) of difficult country, running from Damascus southward to Dar'a, to Jordan via az-Zarqa', Amman, Ma'an, Aqaba into northwestern Arabia, and inland via Dhat al-Hajj and al-'Ula to Medina. The major branch line, 100 miles (160 km) long, from Dar'a to Haifa on the Mediterranean coast of Palestine, was completed in 1905.  

There are indications that show  – although it is not certain –   that the idea of laying the railway line to the Hejaz originated with Izzat Pasha al-Abed; in any case it was he who became instrumental in carrying it to fruition. The project was to build a railway from Damascus to Medina and on to Mecca, ostensibly with the sole objective of facilitating the pilgrimage, but in reality for reasons which were primarily strategic and political. 

A board presided over by Izzat Pasha was set up, and an appeal to the Muslim world issued, stressing the pious motive which had inspired the caliph to build the railway, and asking for contributions toward the cost. The appeal met with a handsome response. At the same time a special tax in the form of a stamp duty was levied throughout the Ottoman Empire, while officials in the Hejaz were “invited” to contribute a percentage of their salaries. 

The work of construction which was entrusted to German engineers began in the spring of 1901, and by the autumn of 1908 the line had been laid to Madina – a distance of close to 99 miles. Of the total cost amounting to some £3,000,000 over 1/3 was made of voluntary donations from all parts of the Muslim world. 

The project was a master stroke of policy in more than one way. It evoked a great deal of enthusiasm throughout Islam, and added to the prestige of the Ottoman caliphate. Strategically it had provided the sultan, at a relatively small cost to his treasury, with a much needed means of overland transport for troops to and from Arabia. Previously he would have had to depend on the slower and costlier sea-transport through the Suez Canal; now he had a railway running entirely in his territory. 

Another important result was the speeding of communications for travel and therefore for ideas in the western Arab provinces. Before the operation of the line, it would take a quick caravan no less than 40 days to travel from Damascus to Medina, while a sea journey form Syria to the Hejaz took from ten to fifteen days. With the railway the two cities were brought to within five days of each other and this abbreviation was destined to make an incalculable difference to the fortunes of the Arab independence movement when it found opportunity to break into open revolt.