A train that runs solely on electricity is called an electric train. It is used to run trains with a non-stop conductor along the track, which can generally take one of the following forms: a readily accessible battery; a third rail raised at track level; or an overhead line connected to poles or supports along the track or the roof of a crossing.
Both third rail and overhead wire systems typically utilize the running rails as the conductor for extraction, but some designs utilize a separate fourth rail for this purpose. In terms of the type of power used, it is alternating current (AC) or direct current (DC).
Data analysis shows that low gear ratios are usually found on passenger engines, while high gear ratios are common on freight units.
Electricity is typically generated at fairly large and profitable generating stations, transmitted to trains, and distributed throughout the railroad system. Only a few electric railroads have production depots and transmission lines, but can maximize access to purchase power from a generating station. The railroad usually provides its own distribution lines, transformers, and switches.
Diesel locomotives typically cost twenty percent more than electric locomotives, maintenance costs are twenty-five to thirty percent higher, and operation is fifty percent more expensive.