Now it is time to mention the electromotive or modern electric train. This one has as propulsion plant a set of electric motors placed beneath the box, in the wheels arrangement, taking the energy from an external source. Since a very large part of its weight is used for the traction system, these vehicles can overcome strong slopes and allow for high accelerations, being very used because of this in mountain railways and secondary lines. In the modern electric train, composed of a number of units often articulated, the profile is aerodynamic and the doors and windows are airtight, so it is required the resupply of air in the interior, and taking advantage of this the air is also conditioned, heating it during winter and cooling it during summer.
With the electric trains were constituted the fast lines, in which the trains do not stop in all the intermediate stations, adding so to the advantage of a high speed the advantage of saving time. In America, where the aerodynamic profile was pioneered, are in use the characteristic two-story wagons known as "imperial wagons", in which the upper story is provided with a wide panoramic view. Sometimes there is even a coffee bar and restaurant with tables.
Transcontinental express "The Canadian" operated by Canadian Pacific Railway in the 1950s. The ensemble consists of a double diesel-electric locomotive towing a number of "imperial wagons".
Cutaway of a diesel-electric locomotive. In this type of locomotive the Diesel engine is not used to mechanically move the locomotive, but to generate electricity by means of an attached generator, which feeds the electric motors that move the locomotive.
1: Driving cabin - 2: Air deposit - 3: Air compressor - 4: Auxiliary generator - 5: Direct current generator - 6: Alternating current generator - 7: Ventilators for cooling the Diesel engine - 8: Diesel engine - 9: Water deposit for cooling the Diesel engine - 10: Charge regulator - 11: Steam generator - 12: Bogies with electric traction motors - 13: Batteries - 14: Fuel deposit.
Another glorious creation in this field was the Italian "Settebello", introduced in 1953. Composed of seven units communicating each other, this fast electric train was provided with luminous six-seat departments, very similar to the contemporary cabinets. Two not less elegant "gazebos" fitted with armchairs, placed in both ends of the train, offered from the wide picture windows the suggestive vision of a landscape escaping at 150 kilometers per hour. Next to the gazebos, in prominences on the roof, were installed the driving cabins. This train, conceived just after the disasters of the Second World War, covered the 632 kilometers of the line between Rome and Milan in less than six hours.
Two units of the Settebello, articulated directly above a central bogie, with the driving cab and gazebo in the fore part and the electricity intake in the rear part.
A specially relevant invention that separates old trains from modern trains was the Spanish system known as TALGO (Tren Articulado Ligero Goicoechea Oriol or Light Articulated Train Goicoechea Oriol). The TALGO is a "super-articulated" train composed of short cars which use an innovative wheel arrangement. The first TALGO was constructed and experimented in United States in 1949; it had been designed by Alejandro Goicoechea and financed by José Luis Oriol Urigüen. The TALGO was officially inaugurated in Spain the 2nd March 1950 and the 14th July of the same year it started the regular passenger service in the line Madrid-Irún-Hendaya.
The TALGO managed to reduce the weight to 90 kilograms per seat, when the equivalent in the lightest trains operating in 1950 was 400 kilograms, while in a Pullman car it surpassed 2000 kilograms. Each one of the units of this articulated train, built in aluminum with exception of the locomotive, has only two wheels, being supported the fore part of each car in the rear part of the preceding car. The length of each car is six meters and the height two meters, being suitable for a speed of 160 kilometers per hour.
In the early times of the railway, cars were fitted with two wheel axes, one at each end; these axes had to be close to each other, because if otherwise it would be difficult to keep the wheels on track during curves, with the consequent danger of derailment. To solve this, in more modern cars the axes were placed in pairs in pivoting carts called bogies, which allowed the cars to be much longer by placing a bogie at each end instead of a simple axis. In the TALGO the wheel arrangement is different; instead of bogies are used pivoting axes on which each wheel is independent and each axe is connected to the subsequent one by two crossbars which connect the ends of the first axe with the center of the second axe; during a curve the crossbars will keep all the axes perpendicular to the rails, provided that the leading axe is correctly aligned by a guide mechanism specially provided for that purpose.
There are some important advantages in this system: the suppression of bogies allows to reduce the height of the cars and hence their center of gravity, allowing for a greater stability, which united to the short length of the cars allows to take the curves with increased safety; speed is increased because the reduced height of the cars means also a reduced aerodynamic drag and also because the cars are made to be very lightweight. All of these factors mean greater safety, speed, economy and overall performance than the obtained by trains until the arrival of the TALGO, one of the most decisive technical advances in the history of railway - and this without having to touch the locomotive itself -.
In its early years the TALGO broke all the railway speed records in Spain by keeping a regularity in the schedule appointed, with an average speed of 80 kilometers per hour. During several years it remained in experimentation as a railway speciality, and after correcting all the defects that appeared, it was ready to start replacing all the conventional railway vehicles in the passenger service. Worldwide famous, the TALGO is considered the most notable Spanish contribution to the progress of transport.Continue reading...