I have been reading old copies of the Railway Magazine from the 1950s and 1960s. The old small format magazines somehow seem more attractive than the glossy larger format modern magazines, perhaps that is a sign of ageing!
In the January 1963 edition of the magazine there is a long article about the railways of Iran which is based on a visit in 1961 to Iran by M.H. Baker MA.
Until the 1930s, Iran was relatively isolated, but from around 1865 various European Countries had sought concessions to construct railways but the Imperial government continued to value isolation above integration.
Baker says that, “Shah Naser-ed-Din … was so delighted with railways that he determined to have one built in Iran.” [1: p21] Shah Naser-ed-Din reigned from 1831 to 1896. He was the first modern Iranian monarch to formally visit Europe. He wrote travelogues about his trips, that also were translated in foreign languages. 
Shah Naser-ed-Din called on a French engineer and concession hunter, Fabius Boital, to build a line from Tehran to the shrine of Abdul Aziz at Rey, 6 miles south of the city. He also received a concession to build tramways in Tehran.  It seems that he was probably short of money and sold “both of these concessions to a Belgian company named “La Société Anonyme des Chemins de Fer et Tramways en Perse,” founded in Brussels on 17 May 1887. The company had a capital of 2 million francs.” [6: p865]
The rail concession allowed the Belgian company to construct and operate a railway line from Qazvin to Qom through Tehran and Rey for 99 years. [7: p45] The principal draw was the number of pilgrims who visited the shrine of Abdul Aziz. However, although “the large number of pilgrims (over 300,000 per annum) who visited the shrine … promised handsome returns for the company, its executives wanted much more: a railway line connecting the Caspian Sea and the south, and passing through Tehran.  This did not materialize because speedy means of communications connecting the north and south of Persia ran contrary to both British and Russian interests.” 
Glyn Williams says that the line, as built, had a track gauge of 800mm it was approximately 5.5 miles in length and had two branch lines of 2.5 miles in length.  The branch lines connected the main line to some limestone quarries southeast of Tehran. The mainline was opened in 1888, the branch lines in 1893. [9: p625][10: p14] The gauge quoted by Williams above appears not to be correct. Further investigation of the locomotives built for the line by Tubize of Belgium indicates that they were built to metre-gauge. 
Tableau des locomotives Tubize livrées pour la Perse (Iran)
n° Année Voie Essieux Destinataire
662 1887 1000 Cn2t / 0-6-0T CF et Tramways en Perse, Téhéran-Rey No. 1
663 1887 1000 Cn2t / 0-6-0T CF et Tramways en Perse, Téhéran-Rey No. 2
664 1887 1000 Cn2t / 0-6-0T CF et Tramways en Perse, Téhéran-Rey No. 3
665 1887 1000 Cn2t / 0-6-0T CF et Tramways en Perse, Téhéran-Rey No. 4
1436 1905 1000 Cn2t / 0-6-0T CF et Tramways en Perse, Téhéran-Rey No. 5
Source : liste établie par Sébastien Jarne
Cn2t = 3 essieux moteurs, vapeur saturée, 2 cylindres, tender (tank in UK terminology)
Construction of the line was difficult as all equipment had to be transferred from Antwerp to Batum on the Black Sea by sea, “then by land through the Transcaucasian Railway to Baku, then by sea again to Anzali on the Caspian Sea, and from there once more by land and on the back of animals, through difficult terrain, to Tehran through Qazvin. … In order to minimize the difficulties involved in the cumbersome process of shipping from Belgium to Persia, [the company] established a workshop in Baku for packing the material from Belgium, bought animals from Tbilisi for transportation, purchased part of the rails from Russia, built boats for river transport, and employed local workers for maintaining the roads.”  These measures proved very costly. [11: p5-6]
“The Tehran terminal, a building in the European style, was situated in the southeast of the capital, near the Darvāza-ye Khorasan Street, some 150 metres from the main bazaar. There were two waiting rooms, one on each end, one for men and the other for women, while in the middle of the building there was a hall for the Shah. Separate wagons were allocated for men and women. The latter formed a considerable part of the line’s clientele. The line itself passed over a 26 metre-long bridge and a plain covered by trees. It was operated by a staff of five Europeans and sixty Persians. 
There was initially a real reluctance among the local population to use what they saw as a fire-breathing monster. “The Belgian company, which did not anticipate such a financially disastrous outcome, complained to the Shah. In order to allay public fears, the shah ordered high-ranking individuals and the commanders of the army to travel with him by train. … Following their example, local passengers, including clerics, began to use the train. But a number of factors caused a decline in the number of passengers: First, the growing number of fatal accidents involved in operating the line; second, the train was labeled ‘Satan’s work’ by clerics, after one of them was run over by it; third, the short distance that it covered meant that many people continued to prefer the leisurely pace of walking or riding on donkeys; and fourth, the relatively expensive price of the tickets was an inhibiting factor.” 
There were five 0-6-0T locos, numbered 1 to 5 (Tubize No. 662-665/1887 & 1436/1905), locally called “Mashin Doodi”, meaning smoke machines. There are very few pictures of the locos serving this short line. This is one. 
Thomas Kautzor wrote in 2011: “One loco was plinthed at the PARS Wagon factory in Arak (290 km southwest of Tehran). … A second loco was photographed by … Arsam Behkish in Mellat Park, north Tehran, in July of 2005, together with an open coach. It still carried a No. 3 and works plate No. 664/1887 on one side and was in very poor condition.” A picture of that locomotive appears at the head of this article and another below. Locomotive No. 3. 
The line continued to operate sporadically until the middle of the 20th century, public use of it gradually declined. By 1901 it was making only a limited number of journeys. This deteriorated even further with the growing use of road transportation.  Its route was parallel to what is now Tehran’s Metro Line No. 1 but it is very difficult to make out any remaining features on Google Earth.
When M.H. Baker visited Iran in the very early 1960s a sporadic service was still operating. He was able to take a few photographs which were reproduced in the article in The Railway Magazine. I have reproduced these images here as they give a good idea of the state of the line at that time. Interestingly, the locomotive shown was in relatively good condition.  ……The front of the station building in Rey (Ray) in 1961. Rey railway 0-6-0T locomotive No. 4 was built in Belgium in 1887 by La Metalurgique S.A. de Construction de Tubize for the opening of the Tehran to Rey line. Baker remarks on its relatively good condition in his article. Ramshackle open-sided four-wheel coaches in the carriage sidings at Tehran in 1961. 
Baker commented that Steam was still active on the line from Tehran to Rey. He goes on to say: “Even the Fridays-only service of recent years was said to have been suspended, and a visit to the once rather grand station in Tehran showed it to be closed up and apparently derelict. In the year behind, however, one locomotive, No. 4, was in steam and another, No. 5, was under repair, so the line has not been finally abandoned. Both engines looked spick and span in their green livery with broad yellow lining. Numbers 2 and 3 were in the shed, with the wheels and frames of what had presumably been number 1. Numbers 2, 3 and 4 are all outside-cylinder 0-6-0 tanks built in 1887 by La Metallurgique Societe Anonyme de Construction at Tubize, Belgium, for the opening of thy line, and bear consecutive works numbers, 663 to 665. No. 5 was constructed by the same firm in 1904 (works number 1436), and appeared identical to her elder sisters.
Also to be seen were a number of decrepit four-wheel coaches. There were some closed saloons with upholstered seats, but. many of the coaches were open-sided and with their hard seats must have been, hot and. dusty in summer, cold and wet in winter, and very uncomfortable at all seasons. At the opposite extreme was the opulent Victorian comfort of the royal coaches built for the train-loving Shah Naser-ed-Din, lying long disused in the back of the carriage shed.” 
Future articles will focus on the lines built in Iran in subsequent years, first from the perspective of the early 1960s and then looking forward to more recent times.
To finish this article here are three further pictures. The first is adjacent to this text and shows another of the locomotives used on the line and displayed on a plinth in Rey, (c) Alireza Javaheri, used under a Creative Commons Licence. 
The second and third pictures (below) show the station building which was the terminus of the old line in Rey. These two pictures are still-frame pictures from a German-produced Video which was made in the early 21st century. 
- M.H. Baker; The Iranian State Railways; in The Railway Magazine, January 1963.
- https://www.worldheritagesite.org/connection/Naser+ed-Din+Shah, accessed on 22nd March 2020.
- https://en.wikipedia.org/wiki/Diary_of_H.M._the_Shah_of_Persia_during_his_tour_through_Europe_in_A.D._1873, accessed on 22nd March 2020.
- Sidney J. A. Churchill, Memo, at the Shah’s Camp, 27 August 1888, enclosure in no. 13, Sir Henry Drummond Wolff to the Marquis of Salisbury, Gulahek [Golhak], 10 September 1888, FO 539/40 (Confidential 5755). Memo entitled: “Memorandum on Persian Railways”, p16 and quoted in reference 5. below.
- http://www.iranicaonline.org/articles/railroads-i, accessed on 22nd March 2020.
- “Acte”: “L’acte de constitution de la société du 17 mai 1887”, Recueil spécial des actes, extraits d’actes, procès-verbaux et documents relatifs aux Sociétés, Brussels, 1887, XV, pp. 865-69, quoted in reference 5. above.
- “Concession”, enclosure in no. 58, Sir Henry Drummond Wolff to the Marquis of Salisbury, Tehran, 8 October 1888, FO539/40 (Confidential 5755), quoted in reference 5. above.
- Otlet à Barbanson, 3 Juin 1887 (copie), Archives Générales du Royaume, Brussels, Fonds Otlet, liasse 4, quoted in reference 5. above.
- Albert Houtum-Schindler, “Persia,” Encyclopaedia Britannica, XXXI, 1902 (10th ed.), pp. 617-627.
- Baron E. Beyens, Commerce et industrie de la Perse, Brussels, 1898.
- Rapport”: “Société Anonyme des Chemins de Fer et Tramways en Perse, Assemblée générale du 4 juin 1888: Rapport,” Archives du Ministère des Affaires étrangères de Belgique, Brussels, dossier 2889 II (1887-1908), quoted in reference 5. above.
- Ḥamida Amāni, “Farār az čarḵ-a-ye nābudi: Eḥyā-ye baqāyā-ye māšin dudi-e ḵ-aṭṭ-e āhan-e Tehrān Šāh ʿAbd-al-ʿAẓim,” Hamšahri, 25 Bahman 1383 Š./13 February 2005, available online, accessed on 22nd March 2020.
- https://www.internationalsteam.co.uk/trains/iran01.htm, accessed on 22nd March 2020.
- http://www.farsinet.com/tehran, acccessed on 22nd March 2020.
- https://en.wikipedia.org/wiki/History_of_rail_transport_in_Iran, accessed on 22nd March 2020.
- https://www.sinfin.net/railways/world/iran.html, accessed on 19th March 2020.
- http://www.museedelaporte.be/patrimoine/?p=1655&pdf=1655, accessed on 25th March 2020.
- https://commons.wikimedia.org/wiki/File:Old_steam_locomotive_in_Rey.jpg; https://web.archive.org/web/20161104221645/http://www.panoramio.com/user/1317158, accessed on 26th March 2020.
- DW Documentary; https://youtu.be/lqSoLVkYYu0, accessed on 25th March 2020.