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 which are often articulated, the profile is aerodynamic and the doors and windows 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 electric trains were constituted fast lines, in which the trains do not stop in all of the intermediate stations, adding so to the advantage of a high speed that 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 fitted 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 tank.
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 equally elegant "gazebos" placed in both ends of the train, and fitted with armchairs, offered thanks to their wide picture windows the suggestive vision of a landscape that escapes at 150 kilometers per hour. Next to the gazebos and protruding from the roof were installed the driving cabins. This train, devised 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 gazebo and driving cabin in the fore part and the electricity intake in the rear part.
A specially relevant invention that distinguishes 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 exceeded 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 by the rear part of the preceding car. The length of each car is six meters and its height is 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 axles, one at each end; these had to be close to each other, otherwise it would be difficult to keep the wheels on the track during curves, with the consequent danger of derailment. To solve this problem, in more modern cars the axles were placed in pairs in pivoting carts called bogies, which allowed cars to be much longer by placing a bogie at each end instead of a simple axle. In the TALGO the wheel arrangement is different; instead of bogies, pivoting axles are used on which each wheel is independent and each axle is connected to the subsequent one by two crossbars, which connect the ends of the first axle with the center part of the second axle; during a curve the crossbars will keep all the axles perpendicular to the rails, provided that the leading axle is correctly aligned by a guide mechanism specially adapted 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 gravity center, allowing for greater stability, which together with the short length of the cars allows to take curves with increased safety, while speed is increased as well because the reduced height of the cars means also a reduced aerodynamic drag and also because the cars are of very lightweight construction. All these factors combined give as result a greater safety, speed, economy and overall performance than that achieved by trains before the arrival of the TALGO, which is one of the most decisive technical advances in the history of railway - and one achieved without having to modify the very locomotive -.
In its early years the TALGO broke all the railway speed records in Spain by keeping a regularity in the appointed schedule, 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 transportation.