Problems and experiments with different pressure of the vehicle on rails resulted in the invention of the straddle-type railway. It used a single rail on which the vehicle moved by means of load wheels while the horizontal drive wheels rolled on its sides or on additional guiding rails. The train on such a track resembled a rider straddling a horse. The first ideas of a straddle-type railway appeared as early as 1820 when a Russian entrepreneur, Ivan Elmanov, built a wooden track for horse-drawn carriages. Similar solutions were employed by: engineers Herman and Botzov in New York, Henry Palmer in England and M. von Prittwitz, who used a straddle-type railway with line traction during the construction of fortifications in Poznań and afterwards in Toruń and in Ulm in Germany.
From the 1860s, Charles Lartigue also worked to develop a straddle-type monorail. The French engineer became inspired during his stay in Algeria where he saw camels carrying heavy loads balanced in panniers on their backs. Lartigue placed a single bearing rail at the level of approximately one metre and supported it on A-shaped trestles. In addition, he placed two horizontal guiding rails on the ground. The locomotive had 2 twin boilers with separate furnaces and funnels, suspended on each side of the bearing rail. In the 19th century the most famous straddle-type railway line, built by Lartigue and his co-worker Fritz Behr, was the Listowel and Ballybunion Railway in County Kerry in Ireland which operated in 1888 – 1924. The route was 9 miles (15 kilometres) long and the train moved with a speed of up to 25 mph (40 km/h). Following the success in Listowel, Lartigue also built 65-mile (105 km) long straddle-type railways in Algiers, and later in Russia, Guatemala and Peru.
The second half of the 20th century brought a wave of new or modernised unconventional solutions, also in monorails, which constituted a peculiar “icon of the future”. A Swedish engineer, Axel Lennert Wenner-Gren, fascinated by the Listowel and Ballybunion Railway design, decided to modernise it. He therefore replaced 5 steel rails with 1 reinforced concrete rail, used tyred wheels and introduced electric traction. This type of railway was named Alweg, from his initials. A German company Alweg-Forschung GmbH took interest in the project by Wenner-Gren and in the 1950s carried out a series of tests and trial runs, building in 1959 a railway line in Disneyland, an amusement park in California.
A test ride of an Alweg monorail – Seattle, 1962
In the 1950s and 1960s numerous lines were built, in particular as amusement lines in parks and exhibition grounds. In the 1960s and 1970s numerous countries such as the United States, Japan, the United Kingdom, USSR and also Czechoslovakia considered building Alweg railways; however the plans were abandoned due to high costs and increased failure rate. In 1962 a line was put into service in Seattle connecting the city with the exhibition grounds. Then again, in 1970, Alweg was put into operation in Osaka for the Expo '70 fair. In 1964 a railway from Tokyo to Haneda Airport was put into operation and with time became a fully functional urban line that still operates to date. The train from Tokyo to the airport passes through two tunnels and the route continues for 5 miles (8 kilometres) along Toyko Bay. And in the city it runs above the streets at the level of the fourth floor. At the turn of the 20th century several more Alweg lines were built in other Asian cities (such as Kuala Lumpur, Naha, and Chongqing), and a number of lines are still under construction, e.g. in Teheran, Jakarta and Moscow.
The Alweg track is a single reinforced or compressed concrete rail. The load wheels roll on the upper surface of the rail and drive wheels – on the sides. The rail is supported on posts which normally have 20 metre spacing. The most troublesome and at the same time the most easily failing elements of tracks are the points, and their construction and operation are very costly. To ensure vehicle balance, sets of 2 tyred load wheels and 2 drive wheels are used. The railcar rests on 2 or 3 sets of wheels (both load and drive) with varying distribution (horizontal and vertical). In addition, in case of failure of the drive wheels, full rubber safety wheels are also used. A significant drawback of the Alweg is fast wearing of tyres, in particular on drive wheels, which considerably increases the costs of operation.