String Transport (also known as Yunitskiy String Transport and Rail Sky Way) is a concept of an elevated light rail transportation system using prestressed rails with prestressed cables ("strings") and cocncrete inside them. It is designed for both freight and passenger services and have two main types of track structure and rolling stock — standard and suspended.
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History
The project was conceived by Belarussian engineer and inventor Anatoly Yunitskiy from the beginning of the 1980s. The first 1/10 scale models of track structure and rolling stock were constructed in 1990-s. Different models were built either with one or two strings. The dynamic and wind behaviour was tested by using a single-string 1/10 scale model in 2006-2007.
The first full-scaled string rail test track was constructed in Russian town Ozyory (Moscow Oblast, Russia) in 2001. This test track had a tube rails supported with a wire rope and spreaders, unlike the monolithic string as proposed now. The length of this test track was about 150 meters. Due to lack of funding the inventors did not produced any railcars for this test track, but used a modified truck ZiL-131 with steel wheels instead of normal road wheels.
Later the project received grants from UN-HABITAT.
In 2008 the pilot route in Khabarovsk was planned. But specialists of Moscow State University of Railway Engineering gave a negative assessment of the project and it was not implemented.
In 2013 more research revealed the feasibility of the use of String Transport Systems for passenger rail in New South Wales.
Company uses crowdfunding with multi-level marketing as a way of financing the project. In 2014 The Bank of Lithuania warned investors that unidentified individuals invite Lithuanian residents to invest in "next-generation string transport" by acquiring on-line shares of the private limited company Euroasian Rail Skyway Systems Ltd without a prospectus approved by a competent authority. In the same year Yunitskiy registered in Lithuania «Rail Skyway Systems Ltd.» and committed in the deal pumping nearly 900 million litas, or roughly 360 million euro. According to several Lithuanian prominent analysts, like Swedbank economist Nerijus Mačiulis, Yunitskiy’s commercial schemes are simply elaborate scams dazzling possible investors with supposedly lucrative profit from holding stake in an array of London-based, ostensibly large-scale asset companies such as «Euroasian Rail Skyway Systems Ldt.», «American Rail Skyway Systems Ltd.», «African Rail Skyway Systems Ltd.», «Australian&Oceanic Rail Skyway Systems Ltd» and, set purposely to Lithuania, «Rail Skyway Systems Ltd.» All these companies’ declared capital reportedly stands at a whopping 235.1 billion British pounds, which would put Yunitskiy, holding a 10-percent stake, on the Forbes’ 10 world richest men list. Lithuanian Bank’s Supervision Department announced that having acknowledged there aren’t signs of a financial pyramid scheme in the proposed business, it, nevertheless, logged an application with Lithuania’s Prosecutor General’s Office on suspicion of illegitimate commercial activity and fraud.
In 2016 the Expert Council under the Russian Ministry of Transport acknowledged SkyWay string technology as innovative and recommended to provide more details. There were no any information about the result of this acknowledged and/or any Government Purchases or contracts with SkyWay.
A prototype EcoTechnoPark with test tracks, showcasing the technology, is currently being built in the town of Maryina Horka, Belarus (Eastern Europe) and is due for completion in 2018.
First samples of urban railcar U4-210 and personal light railcar U4-621 were revealed at a international railway exhibition Innotrans 2016 in September 2016. Later the tests of personal railcar U4-621 have started from the end of 2016.
Track structure
The track structure design is based upon the use of strings built with high-tensioned steel wires inserted into a concrete/resin core and enveloped within a steel shell.
It differs from traditional cable ropeways by using a perfectly flat rolling way to limit the wear, rolling resistance and noise. The functions dedicated to rope tension and rolling way are handled by separate parts. Low span intervals (~50m) coupled with tension much higher than common ropeway allow for low sag, permitting high speed operation.
The string attachments are fixed and there is no tensioning system. The steel thermal expansion over the seasons is absorbed by the modification of the tension stress in the string. As such there are no junction gaps in the rail except for switches, which are built similarly to railway switches. According to inventors, the system can utilize the most direct possible route, but it is possible to create curves by using intermediate supports which locally replace the string with steel structures.
Fatigue handling of the rail, which is an integral part of the string is being studied. As for pre- or post-tensioned beams mixing steel and concrete, fatigue studies are also being carried out. The designer proposes low overall fatigue, considering that the variation of the string tension due to vehicle weight is relatively low.
Rolling stock
String rail transport uses special light-weight railcars and multiple units with traction motors for both passenger and freight transportation. Freight transport also uses freight wagons without motors hauled with locomotives or traction rope. All rolling stock have individual suspension for each wheel with side anti-derailment small wheels like a monorail rolling stock.
String rail vehicles have commercial names "unibus" (universal railbus), "unicar", "unitruck" and "unibike" by analogy with conventional transport, where "uni-" means "unification". Creation of rolling stock for string railways is conducted by SkyWay Companies Group. It carries out design and development of the following types of string transport: