The high power of electric locomotives also gives them the ability to pull freight at higher speed over gradients; in mixed traffic conditions this increases capacity when the time between trains can be decreased. The CAN bus monitor can therefore be used to validate expected CAN traffic from a given device or to simulate CAN traffic in order to validate the reaction from a given device connected to the CAN bus. Receiving: it converts the data stream from CAN bus levels to levels that the CAN controller uses. If the entire network is electrified, diesel infrastructure such as fueling stations, maintenance yards and indeed the diesel locomotive fleet can be retired or put to other uses - this is often the business case in favor of electrifying the last few lines in a network where otherwise costs would be too high. Low-speed CAN uses resistors at each node. An early advantage of AC is that the power-wasting resistors used in DC locomotives for speed control were not needed in an AC locomotive: multiple taps on the transformer can supply a range of voltages. Thus a network transporting both video and audio signals may have to integrate traffic with a very broad range of bit-rates.

This is mostly an issue for long-distance trips, but many lines come to be dominated by through traffic from long-haul freight trains (usually running coal, ore, or containers to or from ports). On the other hand, electrification may not be suitable for lines with low frequency of traffic, because lower running cost of trains may be outweighed by the high cost of the electrification infrastructure. The increasing demand for container traffic, which is more efficient when utilizing the double-stack car, also has network effect issues with existing electrifications due to insufficient clearance of overhead electrical lines for these trains, but electrification can be built or modified to have sufficient clearance, at additional cost. On "French system" HSLs, the overhead line and a "sleeper" feeder line each carry 25 kV in relation to the rails, but in opposite phase so they are at 50 kV from each other; autotransformers equalize the tension at regular intervals. After the French extended the telegraph to the coast of the Black Sea in late 1854, the news reached London in two days. When the pointer reached the position of the depressed key, it would stop and the magneto would be disconnected from the line. These systems could either use standard network frequency and three power cables, or reduced frequency, which allowed for return-phase line to be third rail, rather than an additional overhead wire.

The lower current reduces line loss, thus allowing higher power to be delivered. The majority of modern electrification systems take AC energy from a power grid that is delivered to a locomotive, and within the locomotive, transformed and rectified to a lower DC voltage in preparation for use by traction motors. Regenerative braking returns power to the electrification system so that it may be used elsewhere, by other trains on the same system or returned to the general power grid. The electric train can save energy (as compared to diesel) by regenerative braking and by not needing to consume energy by idling as diesel locomotives do when stopped or coasting. In theory, these trains could enjoy dramatic savings through electrification, but it can be too costly to extend electrification to isolated areas, and unless an entire network is electrified, companies often find that they need to continue use of diesel trains even if sections are electrified. Even on fully electrified networks, it is usually a good idea to keep a few diesel locomotives for maintenance and repair trains, for instance to repair broken or stolen overhead lines, or to lay new tracks. In most of the world's railway networks, what is control cable the height clearance of overhead electrical lines is not sufficient for a double-stack container car or other unusually tall loads.

Due to the height restriction imposed by the overhead wires, double-stacked container trains have been traditionally difficult and rare to operate under electrified lines. Electric vehicles, especially locomotives, lose power when traversing gaps in the supply, such as phase change gaps in overhead systems, and gaps over points in third rail systems. Third-rail systems can suffer disruption in cold weather due to ice forming on the conductor rail. A newer flight control system, called intelligent flight control system (IFCS), is an extension of modern digital fly-by-wire flight control systems. The DC system, apart from being limited as to the maximum power that can be transmitted, also can be responsible for electrochemical corrosion due to stray DC currents. While passwords exist for some safety-critical functions, such as modifying firmware, programming keys, or controlling antilock brake actuators, these systems are not implemented universally and have a limited number of seed/key pairs. The damage is often not limited to the supply to one track, but extends to those for adjacent tracks as well, causing the entire route to be blocked for a considerable time. There are some additional maintenance costs associated with the electrical equipment around the track, such as power sub-stations and the catenary wire itself, but, if there is sufficient traffic, the reduced track and especially the lower engine maintenance and running costs exceed the costs of this maintenance significantly.