A couple more pieces from different foreign sources, the first comes from the SJK Postvagen Forum, the second from a French magazine. As noted in my previous article, I have used Google Translate and Deepl to perform a basic translation of each of these articles and then I have sought to clarify and paraphrase what has resulted from the automatic translation. I trust that these further articles are of interest. …
1. The first is from the Swedish Railway Engineering Journal of May 1961 and is entitled Some Notes from the Journal of Chief Inspector Enar Uhlund on the Building of the Railway between Tehran and Tebriz. 
“In some foreign newspapers, among others, la Vie du Ran No. 785 of 19.2.1961, articles have been written about the work on the Turkey-Iran Railway link, which links the Persian Railway to the European network.” 
(The route is shown below with the length to be constructed shown dotted.)
The planned railway route. 
“At least in Persian territory the route shown is far from exact. The Railway passes through a very mountainous region which will offer both bidders and builder of the line many difficulties. In order to help readers understand these issues, I want to provide some insights into the building of the now completed line between Tehran and Tebriz.
In 1955 and 1956, I served as a manager in a Persian contracting firm which completed a 20 km section of the around 150km southwest of Tebriz.
The Persian state directed construction management and control through a distinct railway construction organization, separate from rail administration, which also provided track laying in-house.
Terracing works, art buildings and houses are being contracted by domestic, smaller companies, each of which had a contract plot covering all works on a section of 20-30 km in length.” “The design work had been carried out by the Danish consultancy firm Kampsax about 25 years earlier. This company had done a great job of producing drawings, job descriptions and other documents, which would enable the work to be undertaken with a minimum of technically trained operatives. The only fault with their plans was that they were no longer up-to-date. For example, structures were designed in stone or mass concrete, easily available in the 1930s. An example is shown in the adjacent picture.” 
“Terracing works, railway structures and houses were built by smaller domestic companies, each of which had a contract covering all work on a section of 20-30 km in length.
In addition to drawings and work descriptions, preliminary mass information and a pricing list covering all types of work are included in the tender documentation and tenderers may also qualify their tenders by providing a general discount in the list prices
Given the lack of firm control and supervision as well as the flexibility in pricing, the system favoured the contractor. The opportunity for lucrative work was increased significantly. For example, most of the prices, associated with bridge foundtions were very favorable, which meant that the foundations were built to a good size, both in terms of width and depth. In contrast, the prices for house-building work were low, so contract terms were adhered to rigorously, work was sluggish and these structures were often of poor quality.
The lack of supervision is evident from the fact that all the contract overseers were also employed as supervisors of the contractor, a peculiar relationship to a Swedish eye.” 
The very low wages – a day’s wage for a worker amounted to just over 2 Swedish Kroner (SEK) – in association with the difficulty for a small company to look after machinery meant that the degree of mechanization was very low. The only motor-driven devices that appeared were a number of trucks and some motor pumps.“The workforce amounted to a maximum of about 2,000 men, which, despite the very small numbers, caused some accommodation problems. Billets, often of an incredibly simple type had to be be arranged and each worker was assigned a daily bread allowance of about 1kg’s weight. … These bread-cakes were, in many cases, the only food the workers received. The workers were treated very harshly, and there were occasional supervisors who felt that they did not fulfill their duty unless they whipped at least two workers every day.” 
“The contract included a number of larger bridges, the largest of eight 10-metre spans. These bridges, which were built as circular arches in stone, are undeniably very beautiful and the skill of the stonemasons is impressive. The next four relatively poor quality pictures show the bridges under construction.” 
Bridge with all spans of 10 m under construction. The piers are of limestone, the arches of gray red, harder rock. Note the corbel s and the masonry plinths for the arch vaulting. Bridge with eight spans of 10 m under construction. One arch just completed, 20 metres above river level. A different bridge, this time with five spans of 10 m under construction. Track height above the river level will be about 30 metres. Bridge with 5 spans of 10 m under construction. Each stone is carried on a stretcher by two men. 
“The experience that a Swedish engineer has in a workplace of this kind, is primarily that the difficulties lie in completely different areas than you might expect. For example, it is not always easy to be in charge of the technical management of a project when you are the only one in the workplace who can use a theodolite, when your manual labourers speak nothing but Persian and cannot even read our numbers or letters.
It felt particularly important to engage in such work at a stage when the terracing work being constructed for the entire line. Now, however trains are running on the line to Tebriz and just a little to the West of Tebriz work is underway on what will be the last link on a line between Europe and Iran.” 
2. The second is much more recent and comes from a French Journal – a 2016 edition of Objectif-Rail  As above, the English text started off as an automatic translation and has then been refined/paraphrased to make the greatest sense in English. The text of this article is in Italics.
The Trains of the Country of the Ayatollahs
Iran is a little-known and hitherto inaccessible country, it has a railway network steeped in history and booming since the end of economic sanctions. Explore the railway network of the Islamic Republic of Iran (RAI): breathtaking landscapes of the Trans-Iranian Railway traveled by indestructible American diesels and in Tehran, a city served by a modern suburban network equipped with State of the art Chinese equipment. This is a visit to an exciting railway world!
lrân is a territory of 1,648,000 square kilometres, about three times the area of France. It had a population of 81 millions inhabitants in 2015 but only 19 million in 1956. The population has grown fourfold in around 60 years! The City of Tehran has 13 million inhabitants. The other major cities are lsfahan (3.5 million) Mashhad (3 million) and Tabriz (1.6 million). In 2011, 33 million tons of goods and 29 million passengers were transported by rail. This is between 9% and 11% of total transport in Iran. The amount of freight is growing rapidly. The network owner and the main rail operator is the “Railways of the Islamic Republic of Iran” (RAl). Literally, RAI stands for “Rah-e-Ahân lran” and means Railways of Iran. There are private operators for the services of travelers, many of whom are RAl affiliates, and for freight, like Alborz Niroo, a private operator.
The timid and tardy start of building a rail network
It was a long time before Iran built a railway line of note. Iran was still called Persia that time. The country was a victim of a weak and confused government, subject to foreign interests and to archaic conservative religious views. The two great foreign influences were Britain and Russia. Britain wanted to protect access to its Empire in India while Russia wanted to extend its imperial influence by extending its territory to the south.
Conflicts between Russians and British, who both sought to increase their influence and develop their interests in the region, resulted in the first credible initiatives in railway construction being stopped. There were several attempts but they all failed, with the exception of a 9 km metre-gauge line opened in 1887 between Tehran and Rey to transport pilgrims to the Abd-a-Azim mosque. Apart from some narrow-gauge military and industrial networks concentrated mainly in the oil fields and the northern forests, the first significant lines were finally opened during the First World War when Russian, Ottoman and British troops occupied the country.
The first line of 148 km from Jolfa (at the Russian border) to Tabriz was built
to the Russian gauge of 1524 mm in 1916. Otherwise, the Persian map remained empty of railways until a wide-gauge (1676 mm) extension of was opened in 1922 from Quetta in India under English authority (today in Pakistan), reaching the border at Mirjaveh and continuing into Iran to Zahedan. This line remained isolated and economically marginal until 2009. It is expected that it will soon be linked to Bam, thus forming a direct link from India to Turkey.
The railway was then taken over by the Russians north of Tehran and by the British to the south. The Trans-Iranian Railway became the famous “Persian Corridor” (the main roads between the Persian Gulf and the Caspian Sea were also part of it). This supply corridor was essential for supplying military equipment under the “Lend-Lease” agreement and supporting the Red Army through the “back door.”
For the record, the “Lend-Lease” program was an armament plan implemented by the USA during the Second World War intended to provide friendly countries with war materiel without intervening directly in the conflict (before the entry into war of the United States), which de facto put an end to the American laws of the 1930s on neutrality. The Trans-Iranian Railway was not designed for military use, nor for the intense traffic which would have to travel over its rails during the Second World War.
There was very little suitable rolling stock for the war effort. The main line locomotives were:
– 49 No. 140 (2-8-0) type steam engines from German manufacturers Krupp, Henschel and Maschinenfabrik Esslingen, known as “Ferrostaal” locomotives. The company had been a subcontractor to Kampsax (the company which organized the construction of the line); and
– 16 No. Henschel locomotives of type 150 (2-10-0).
In addition, the Iranian State Railways owned a dozen Nohab 141 (2-8-2) locomotives which were unusable on the mountain sections and four powerful Beyer Peacock Garratts, type 241-142 (4-8-2-2-8-4) for the long 2.8% gradients in the north section between Pol-e-Sefid. and the summit at Gaduk.
From all of these, the occupying forces determined that only the 150 (2-10-0) Henschels were in “good technical condition”.
To process the expected tonnages, the English sent about 150 No. 140 (2-8-0) LMS 8F locomotives which were assembled in Iran by 3 military railway companies: the “190 Railway Operating Company”, the “153 Railway Operating Company” (exploitation) and the “155 Railway Workshops Company “(workshops and maintenance).
In 1942, the American army took over on the southern section. It brought first 91 No. 141 (2-8-2) “War Department” Ministry of War of the USATC series (Corps of Transport of the United States Army) Locomotives and then 75 No. Alco diesels of 1000 horsepower of type RSD-1 in three batches.
Before the invasion of Iran, the Trans-Iranian Railway only carried around 200 tonnes of freight per day. British troops reached an average of 1,530 tonnes per day towards the end of 1941, then the Americans largely exceeded this level with a daily average of 6,489 tonnes in 1944, mainly thanks to Alco RSD-1 diesels. The Soviets in the north used the German machines and the four Beyer-Peacock Garratts repaired by the British in the workshops in Tehran.
The Russians had to face the toughest gradients, but they didn’t have as many tunnels as the southern section between Andimeshk (146 metres above sea level) and Dorud (1454 metres).
There are 144 tunnels on the 266 km of the mountainous part of the line that the American military railway workers called “the Metro” (subway). In the tunnels, smoke and combustion gases from steam engines sometimes made the air unbreathable, creating grueling working conditions for the crews. Water supply was easier in the Soviet zone, water was a scarce resource in the British zone, before supply collapsed completely. Several stations were supplied with water by tank wagons. Cleaning the boilers was difficult due to water restriction. Cleaning was a frequent requirement before the introduction of water treatment. The difficulties linked to steam traction (water supply, washing of boilers, exhaust gas from fuel oil heaters and other fumes in tunnels, etc.) were such that its use represented a constant limitation of the transport capacity. That is, until the Americans put the Alco RSD-1 diesels into service. The USATC began by requisitioning 13 No. Alco RS-1 type 1000 horsepower BB (Bo-Bo) engines already built for American customers, and had them converted to CC (Co-Co) type RSD-1 better suited to the lighter rail of the Trans-Iranian Railway. A second batch of 44 No. RSD-1 machines was purpose-built for Iran and a third batch of 18 engines was put into service in April 1943. These were stabled further north in Qom in 1944 to circulate from Andimeshk to Tehran. Double traction was used on the most difficult sections.
All RSD-1s were retired from service after May 1945 at the end of the Second World War in Europe and returned to the USA for the most part. At least two of them are today preserved in the USA on heritage lines.
In addition to the diesels, the Americans also introduced into Iran between October 1942 and November 1943 ninety-one 141 (2-8-2) “Middle-East” type locomotives (identical to those present until the end of the steam in Turkey). After the war, 70 entered service with Iran Railways (RAI).
Between December 1941 and May 1945, more than 3 million tons of goods were carried by the Trans-Iranian Railway. During the occupation, the railway network was only increased by lines meeting military needs. An example is the new line which was built to connect with another port was built at Khorramshahr on the Persian Gulf because the quay at Bandar Shahpur was too small to handle the entire volume of imported goods.
The Development of Railways after 1945 …
The expansion of the rail network initiated during the reign of Reza Shah resumed after the departure of American troops in late 1945. But as the Americans left the country according to the plan exactly 6 months after the end of the war, the Russian troops left much later after trying to annex the Iranian province of Azerbaijan located in the Northwest of the country.
The northern lines were not taken over by RAI until May 1946. The Americans paid significant compensation to the Iranians for the use of their rail network during the war, and the Russians paid nothing at all.
It was a good investment, as large orders for American diesel locomotives followed later. The steam and diesel locomotives brought by the British and American troops were almost entirely withdrawn from service and dispatch to their country of origin or other places, apart, that is from 70 No. 141 (2-8-2) “Middle East” Class locomotives mentioned above.
During the following years, Iran was able to connect its rail network with that in Turkey.
Here is the list of the most significant line openings:
A rapidly expanding rail network
Iran has mainly relied on road transport, building a series of highways. Inexpensive and sometimes even subsidized fuel makes car journeys accessible to a large part of the population, and road lorries represent the bulk of the transport of goods. At the start of the 20th century, Iran had a population of 12 million. It is around 81 million today, which has led to a huge increase in the demand for transport, a resulting increase in pollution in big cities and a high road mortality. Rail only provides 9% of all transport. This is why Iran has announced an ambitious program for the construction of railway lines, undermined by the 1979 Revolution and more recently by several years of economic sanctions until they were lifted in 2015 in conjunction with the Iranian nuclear program being placed on hold. Despite these difficulties, several lines have been put into service since the 1990s, and investments continue, including electrification and a high-speed line project. A list of these lines is provided below, some of which are still under construction:
Other major projects are in the pipeline and will be co-funded by the private sector. Feasibility studies have recently been carried out for an ambitious project of a line along the Persian Gulf from Ahwaz to Bandar Abbas. In 2010, the Iranian Islamic State Railways intended to expand their network by around 11,000 km to 25,000 km by 2025. Elsewhere in the world, only China has such rates of expansion.
The first high-speed line between Tehran and lsfahan is under construction. For a long time, the electrification of the main Tehran to Mashhad line has been in the cards. It was on this line that the French turbotrains of the RTG type (rated at 160 km/hour) were run in Iran.  There are also plans to transform the Tehran to Mashhad electrification project into a high-speed line.
It is probably only after a complete return to normal following the lifting of economic sanctions (2015/2016), and when the price of oil rises again, that Iran will be able to finance its ambitious plans for the construction of an additional 850 km long high-speed line suitable for travel at 250 km/hr. For now (2016), there is still a shortage of many things that Iran requires to import. Railway construction sites are thus running late or have been completely stopped. The line to Azerbaijan, Qazvin – Rasht – Astara, for example, should have opened in 2011, but it is still under construction (2016).
Motive Power: the domination of American diesels
The first diesel locomotives in Iran were a series of 24 light mechanical trans-mission shunting machines of 180 horsepower built by Davenport Locomotive Works, of Davenport, Iowa, USA, and delivered to Iran in 1942 (20 further units joined them in 1949-50). The order for these diesels was placed before the Allied invasion of Iran. In the same year, the first Alco RSD-1 diesels arrived in Iran, when the British forces operating on the Southern Division of the Trans-Iranian Railway were replaced by the American forces of the USATC. At the end of the war, all the RSD-1 locomotives returned to the United States but the experience of diesels had been positive. So it is not surprising that the Iranian railways decided on a complete and fast transition to diesel power. However, they had spent a lot on the delivery of a final series of 64 huge new type 151 (2-10-2) steam engines of English origin (from the Vulcan Foundry, series 52.11 to 52.74).
Ordered in 1951 and delivered in 1953, they had a very short lifespan due to the arrival of new diesels. On 20th March 1961 (at the end of Iran’s year 1339), there were still 252 RAI-powered steam locomotives on the network, but only 35 of them were in working order. In the mid-1950s, the RAI ordered their first EMD (General Motors) diesels. They were 136 No. G12 type 66 machines of 1310 horsepower, and they were delivered between 1956 and 1962. Many are still in service today. These reliable machines convinced the management of the railways to order 30 No. more powerful CC (Co-Co) G16s, built in 1959, and a series of 13 No. BBs (Bo-Bos) of 875 horsepower type G8 in 1959. Thanks to these machines, the end of the steam in Iran occurred in the mid-1960s.
Other orders followed but the relations between Iran and the USA cooled completely with the Islamic Revolution and the Iranians found other means of obtaining the American locomotives needed on the international market. BB (Bo-Bo) G22W and CC (Co-Co) GT26CW locomotives formed the backbone of rail traffic in the mid-1980s. After the 1979 revolution, American locomotives no longer came directly from EMD. They were imported from Yugoslavia, Canada or South Korea where they were built under license. But they were still quite American!
During the years of economic sanctions, it became increasingly difficult to obtain these good old, reliable and durable diesels. Other manufacturers took the opportunity to deliver their locomotives. But as good as the products of Siemens or Alstom/Ruston, the American classics were highly appreciated for their robustness (and even “indestructibility”!), Their reliability, their ease of maintenance, their high load-pulling capacity and even their ease in digesting fuels of variable quality. You can power an EMD or GE engine with anything that smells near enough to the smell of diesel, even heavy fuel oil is acceptable and does not stop the engine. The indifference to both the quality of the fuel and the harsh climatic conditions are advantages that the new highly efficient diesel engines will never achieve. This is why, despite the arrival of a lot of new locomotives in recent years, the good old GF26CWs will not disappear anytime soon. These machines are still at the heart of the locomotive depot on some of the most difficult parts of the network, notably the Trans-Iranian Railway.
Alstom, Siemens, Chinese: the competition!
Recently, Alborz Niroo, one of the private operators in Iran, bought 77 No. used GT26 locos from South Korea and put them into service at the head of heavy trains of steel drums and iron ores and other resources on desert lines like lsfahan to Yazd. The RAI locomotive workshops are in Karaj (Tehran). Alborz Niroo is building a new workshop for its fleet of 77 No. American locomotives and 2 No. Chinese locomotives in Sistan near Isfahan. However, due to the economic sanctions, it is still difficult to buy spare parts. A major overhaul with replacement of a significant number of parts can cost more than a million US dollars in spare parts. But the Iranians are making this investment because the American locomotives will have a long life in Iran. They are ideal for the terrain. It should also be noted that most railways operating in arid and hot deserts are equipped with American machines. This is, for example, the case of Etihad Rail in the United Arab Emirates, a brand new network equipped exclusively with modern EMD machines. But there is more and more competition. The 100 CC Co-Co engines of type AD34C Alstom/Ruston from 2000-2009 (externally similar to Prima Alstom) have the great advantage of being able to be easily converted into electric locomotives when the electrification of the Iranian railways begins. In 2006, Siemens, Mapna and the RAI signed a contract worth $450 million for the supply of 150 mono-cabin, 2400 KW BB (Bo-Bo) locomotives for passenger trains. 30 machines have been built in Europe and 120 in Iran under the cover of a technology transfer agreement. Nicknamed “Iran Runner”, they have been adopted as the best locomotives for fast passenger trains and RAI plans to increase speeds thanks to them.
The first locomotive was built by Siemens in early 2010 and was able to be delivered thanks to a special agreement due to the sanctions which permited such deliveries. The last 5 locomotives need to be delivered in autumn 2016 by Mapna. In May 2016 we were able to see, at the depot in Tehran, No. the 1646 carrying out its first tests after delivery. Since it will take longer than expected to electrify a large part of the network, RAI will have Mapna build 38 additional units. Negotiations with Siemens have already started in this direction. Iran also bought Chinese machines, but the DF8Bi ( ‘i’ stands for produced in Iran) was a failure. These machines were only effective as long as Chinese technicians took care of them during the warranty period. Shortly thereafter, outages occurred and have continued continuously to this day. The DF8Bi may well be the last diesel locomotives delivered by China before for some time.
In Iran, when any machine or device of any kind breaks down, before considering repairs, it is usual to ask if it is of Chinese manufacture and if so to give up all hope.
Due to current electrification projects, the purchase of additional diesels may well cease. However, reducing the size of the fleet is not an option, given the growth in freight traffic, the construction of new lines and the possibility of creating a new transit route between Asia and Europe. So we can be sure that the good old American diesels will still last a long time. And for the Trans-Iranian Railway, they will remain the go-to locomotive for freight traffic.
Diesel Locomotives in Iran. …
Electric Locomotives, self-propelled vehicles, turbotrains and railcars …
Alongside its diesel fleet which is the pride of the network, Iran also has electric locomotives and railcars:
- The Tabriz-Jolfa line (formerly broad-gauge, now in standard-gauge) electrified in 25KV 50Hz is served by 8 Swedish BBs (Bo-Bos) ASEA RC4 dating from 1979-80.
- The Tehran metro is of recent construction – the first line dates from 1999. It is served by electric self-propelled vehicles of Chinese origin.
- One of the lines of the Tehran metro, line 5 Téhéran-Karaj-Mehrshahr is 43 km long and of the Réseau Express Régional type (RER).  It is served by units of 8 cars with 2 levels and 56 Chinese electric locomotives similar to the SS8 locomotives of 3200KW. 
The company ANF  built and delivered four RTG Turbotrains  to Iran by 1975, to run at 160 km/hr between Téhran and Mashhad on a single track line with manual points, U33 rails  and joints on wooden sleepers. The RTGs had to be adapted to the hot climate and especially to the sand which entered the ventilation openings of the turbines. They were stopped during the Iranian revolution of 1979 then 3 trains were put back into service in 1990. The last 5 SNCF RTGs based at the Vénissieux depot were sold to Iran in 2004 to provide spares for the other active sets. But some have been repainted in the colours of the Iranian Railways and put into service between Tehran and Mashhad. In 2008-2009 the trains remaining in service were converted to diesel trains with Volvo engines. In October 2015, one train still in service was demotorized and towed by an “Iran Runner” diesel on the Tehran to Mashhad line. We do not know whether this situation continues today (2016) or how many RTGs without an engine have been driven in towed trains.
BR Class 141 English railcars (Pacers)
The first railcars appeared in 1940. More recently, 12 two car railcar sets of British origin were bought from BR (British Railways) in 1997 (ex-BR Class 141) and used until 2005 (Rated for a maximum speed of 121 km/hr). Built by British Leyland in 1984, they were not a success in Iran. 
The Siemens Paradise DH4-1 trainsets
In 2001, RAJA Passenger Trains, the RAI passenger subsidiary, placed an order with Siemens Austria for 20 diesel fast-running trainsets with hydraulic transmission composed of 4 carriages all motorized and fitted with air conditioning, suitable for speeds up to 160 km/hr and intended primarily for the Tehran to Mashhad line. They were delivered in 2004-2005, they were equipped with MAN engines with a power of 4×588 KW.
The Hyundai Rotem multiple units
In 2004, the Korean manufacturer Hyundai Rotem won a contract for the supply of 150 diesel multiple units. The first 24 trains were built in South Korea and 24 trains were then to be assembled in Iran by the Iranian railway manufacturer Irico from kits. The remaining trains were to be built entirely by Irico with support from Hyundai Rotem. However, the international sanctions imposed in 2010 only made it possible to deliver 68 items without payment to the Korean manufacturer. Irico resumed construction of the trains in July 2015 and was able to deliver the 17th train assembled in Iran to RAI in February 2016 . With the lifting of the sanctions, Hyundai Rotem has announced new negotiations with RAI to recover the payment of the $76 million owed to it and to complete the initial order.
Discovering Iranian railways in 2016
Since the lifting of economic sanctions, it has become easier to travel to Iran. In particular, it is possible to buy services such as hotels and rentals by car or coach. You need to have a visa for each trip, but that does not present any other difficulty than filling out the forms correctly and queuing twice at the embassy.
The other problem for the railway lover is the ban on photographing trains (and other sensitive subjects) in Iran. In the midst of nature, far from cities or outside major stations, this does not present too many risks. It is important to be discreet. So, individual trips for rail photography are possible.
A small independent group of three amateurs successfully completed such a trip in April 2016 without any notable incident other than a puncture. But one can always come across formidable “Guardians of the Revolution” which can create more or less serious troubles. And above all, there are areas that are strictly prohibited, but that are not visible on the map or on the ground. Fortunately in May 2016, Bernd Seiler, the dynamic boss of FarRaiI Tours (httplIwww.farrail.net) organized a first trip for photographic and rail video enthusiasts, with official authorization to photograph trains wherever the route (duly validated and approved) took the party, but he could only obtain this privilege in return for the “purchase” by Far-Rail of a useless charter train, which served as “cover” for the payment to the Iranian railways (RAI) of substantial financial compensation. As usual, Bernd did an excellent job. Besides the free visit (without orange vest!) to the Tehran workshops, the group benefited from access to sites along the length of the Trans-Iranian as spectacular as they were inaccessible. The group were offered the use of inspection and maintenance vehicles which transported them to rural stations and sites for photography which allowed the pictures in the article (see the Appendix) to be taken. The only regret was the presence of fog in the region from the Caspian Sea to the pass at Gaduk in the Elburz Mountains, which prevented a good pictorial record of the fascinating loops and structures near Veresk. But even the best of the organizers is not in control of the weather … FarRail Tours will be organizing further trips to Iran, the first in the spring of 2017.
- The reference information for this extract was provided in Swedish: NAGRA GLIMTAR FRAN ETT PERSISKT JARNVAGSBYGGE Av overinspektor Enar Uhlund, DK 625.111(560), it comes from Jarnvags-Teknik (Railway Engineering) of May 1961, https://www.postvagnen.com/sjk-forum/showthread.php/12693-Irans-Järnvägar/page2, accessed on 2nd April 2020.
- Jean-Marc Frybourg and Bernd Seller; Globe Trotter: Des Trains au Pays des Ayatollahs; in Objectif-Rail No. 77 September-October 2016, p68-86. This article is written in French. A copy of the article is provided below in the Appendix.
- https://en.wikipedia.org/wiki/SNCF_Class_T_2000, accessed on 8th April 2020.
- https://en.wikipedia.org/wiki/Turbotrain, accessed on 8th April 2020 – “Four units of Turbotrains were introduced in Iran in 1974/5 with max speed of 160 km/h (99 mph) between Tehran andMashhad that later in 2008 were converted to DMU by substitution of diesel instead of turbines.”
- The Réseau Express Régional (English: Regional Express Network), commonly abbreviated RER , is a hybrid suburban commuter and rapid transit system which serves Paris and its suburbs. The RER combines the operations and roles of a local city-centre underground rail system and suburbs-to-city-centre commuter rail. Inside the city centre, the RER functions much like the Métro, but is faster as it has fewer stops. This has made it a model for proposals to improve transit within other cities across France and elsewhere in the world. 
- https://en.wikipedia.org/wiki/Réseau_Express_Régional, accessed on 9th April 2020.
- e.g. “Regional Rail for New York City – Part I” dated 16th July 2009; https://www.thetransportpolitic.com/2009/07/16/regional-rail-for-new-york-city-part-i, accessed on 9th April 2020 and quoted in reference  above.
- The Shaoshan 8 (SS8) is a semi-high-speed electric locomotive used on the People’s Republic of China’s national railway system. The SS8 is based on its predecessor, the SS5, and was developed and built by CSR Zhuzhou Electric Locomotive Works. 
- https://en.wikipedia.org/wiki/China_Railways_SS8, accessed on 9th April 2020.
- Ateliers de Construction du Nord de la France was a French locomotive manufacturer, based at Crespin in the Arrondissement of Valenciennes, northern France. Later known as ANF Industrie or ANF the company was acquired by Bombardier Transportation in 1989 and is now part of Bombardier Transport France S.A.S. 
- http://www.eastbank.org.uk/turbo.htm, accessed on 9th April 2020.
- Gas turbines: After the encouraging results obtained during the first tests on an experimental gas turbine rail car in 1967, the SNCF brought 14 ETG turbotrains into service (4 different bodies, mixed gas turbine and diesel engine power-plant) and then ordered 39 RTG turbotrains between 1970 and 1974 (in service in 1976) of a more sophisticated kind (5 coaches, all-turbine power-plant, new-type bogies and air-conditioning). All these turbotrains were being used successfully on high-speed express and non-stop services on non-electrified lines of medium traffic density. A point to note is that six French-built RTG turbotrains are in service in the United States and four in Iran. 
- Resolutions of the Council of Ministers of Transport and Reports Approved in 1976; The European Conference of Ministers of Transport Volume II; p137; https://books.google.co.uk/books?id=sUJcAQAAQBAJ&pg=PA137&lpg=PA137&dq=RTG+turbotrains+in+Iran&source=bl&ots=OrVFSvDU57&sig=ACfU3U00c2KRnbsTuFSlFOOuCZhVKo92rQ&hl=en&sa=X&ved=2ahUKEwj8pviyntzoAhVykFwKHQvPBC4Q6AEwEnoECAwQLA#v=onepage&q=RTG%20turbotrains%20in%20Iran&f=false, accessed on 9th April 2020.
- https://en.wikipedia.org/wiki/ANF_Industrie, accessed on 9th April 2020.
- The profile of U33 rails is shown on the adjacent diagram. https://rails.arcelormittal.com/types-rails/transport-rails/european-standards/rail-u33-46e2, accessed on 9th April 2020.
- Neither were they considered a success in Great Britain. However, it seems as though the Iranians were much quicker at abandoning them than the British have been!
A copy of an Article in ‘Objectif-Rail’ No. 77 in 2016.