We are starting a series of publications in which we will compare the SkyWay technology with existing modes of transport, study their characteristics and find out how the string transport complexes differ from well-known and familiar to us ways of transporting passengers and goods, and how the string tracks be profitable alternative to conventional transport means.
A little bit of history.
This mode of transport first appeared in Russia in 1820: Ivan Elmanov, a resident of the suburban Moscow village of Myachkovo, built «a road on pillars» on the upper crossbeams of which, there were rolling trolleys, pulled by horses.
Project of I.Elmanov's monorail road (1820)
In 200-year period after Elmanov and Palmer roads, the world has seen dozens of monorail projects that differed from one another in terms of technical design and execution, up to the use of gyroscopes, jet engines and magnetic cushions.
Wuppertaler Schwebebahn; a suspended monorail road in the German city of Wuppertal, which has gone down in history as the first monorail to be put into operation, is also worth mentioning. It remains operational and currently carries around 85,000 passengers per day. The line has survived two world wars and continues to generate profit, remaining a clear example of a safe way to transport passengers. Perhaps, the secret to the success of the Wuppertal road was that in the valley of the Wuppert River at the beginning of the 20th century, it was difficult to lay a land or underground railway line, and a monorail could be built directly above the river.
Perspectives, prospects…
But the Wuppertal's experience is rather an exception to the general rule: today, the monorail is among the transport market outsiders. It would seem that the adequate idea to isolate transport routes by placing them above the ground should ensure a high level of safety and speed of passenger and cargo transportation. But in practice, even modern types of monorail roads cannot boast of outstanding performance or low capital costs of construction. It is often expensive and inefficient. Even the high-speed Maglev, which can travel at speeds of up to 600 km/hour, has proved to be economically inefficient due to the substantial construction and maintenance costs. Another confirmation of this is the experience of the Moscow monorail operation, which in 2017 the city administration switched to the excursion mode of operation, and then raised the question of the expediency of its use due to low profitability.
Monorail and SkyWay
The visual similarity of monorail roads with the string transport complexes is the basis for some «experts» to judge the market prospects of the SkyWay technology. The logic of Yunitskiy's opponents here is simple: Transport looks similar, so if monorail is undemanded, SkyWay will repeat its fate. But there is only one similar feature in these transport systems: they both move on a special overpass. And there are a lot more design differences. However, let's take them one by one.
Overpass
Practically, a reinforced concrete or metal overpass is almost always used for monorail roads. The cost of its construction varies from 17 to 100 and more million USD per kilometer.
“Wuppertaler Schwebebahn Overpass” (left) and the flexible SkyWay track structure (right)
In the string transport systems, due to the use of prestressed steel structures, the flyover can bear high loads with low material capacity. This not only significantly reduces the cost of the SkyWay tracks building, but also gives advantages to the string transport in terms of aesthetics: instead of massive monorail overpasses, you can build light, openworked and at the same time durable structures that will not look monstrous against the backdrop of the city panorama, and beyond it.
Running gear
Most monorail systems (except for the magnetic cushion trains) use rolling stock with running gear equipped with pneumatic tyres. This solution has a number of advantages as well as significant disadvantages.
The use of pneumatic tyres leads to significant energy consumption during the motion. For example, in comparison with railway transport, energy losses can differ in 5-7 times, as pneumatic wheels have greater rolling resistance and inertia of rotation in contrast to the systems of «steel wheel — rail ».
Theoretically, trains on pneumatic tyres can overcome steeper gradients (over 15%) than rail systems. In practice, however, this advantage is insignificant, as it requires a more efficient power unit, additional energy consumption, and ultimately will lead to decrease in the level of comfort for passengers.
In addition, pneumatic tyres are more susceptible to the weather conditions, in particular, to the icing of the track structure in winter. This requires additional clearing of the overpass from snow and ice, or placing the running gear in an isolated box protected from precipitation (Safege system), which hampers its maintenance.
The running gear on the pneumatic tires of the Moscow monorail (left) and the running gear of SkyWay (right)
In the construction of the running gear of the SkyWay rolling stock, there is implemented a scheme in which the steel wheel rests on the surface of the rail. Unlike a pneumatic tire, the SkyWay wheel has low rolling resistance due to the narrow (in the direction of rolling) contact spot, which ensures low energy consumption of the rolling stock.
Besides, the use of the steel wheel assembly solves the problem of icing, because such a system does not require additional cleaning of the track structure. The SkyWay rolling stock running tests at the EcoTechnoPark have proven this in practice.
Flow capacity
From all traditional monorail systems, which can be noted, the most commercially successful monorail roads are the ones by Japanese company Hitachi and Canadian Bombardier. The key to their profitability was the use of the ALWEG system in the design of the running gear: two support wheels are on top of the rail + four support wheels on the sides. It is this scheme that eliminates the lack of low speed of conventional monorail and helps to cope with the large passenger flows of up to 137 thousand passengers per day.
To compare: the speed of motion in the SkyWay urban complexes can reach 150 km/h, and thanks to the use of intelligent control systems of the rolling stock, theoretical peak capacity of such a system at 20-hour work is 360 thousand people per day in one direction (taking into account the two-second allowed interval, as well as 10-base capacity of a single module). In addition, the SkyWay transport systems' efficiency can be further improved by increasing the capacity of the modules and combining them into trains.
Conclusions
The two transport systems can be compared for a long time, but even on the above points it becomes clear: the overpass transport can be different, and the design differences between similar complexes at first glance can be very significant. So significant that one system can be an expensive toy with very vague market prospects for quite a long time, while the other one can effectively address any existing transport problems.