With its appearance, the railway has played a big role on a global level as it can transport large loads and people over long distances. It is very flexible, durable and long lasting. As all things developed, so did the railway, which in a certain period of time came from a steam locomotive to an electric locomotive, and still to a floating magnetic locomotive (powered by magnetic force). The electric locomotive proved to be a locomotive that has a large and most common application in railways. Along with it, a diesel locomotive is used, which is less in function, but is still needed. In order for the electric locomotive to function, it was necessary to construct a transformer that has the function of converting high voltage to low voltage. Transformers are an integral part of entire electrical networks that are placed in substations at certain distances. They are an integral part of the whole system without which that system would not be able to function. Since they are an integral part of entire networks and play an important role in the entire railway infrastructure, it was necessary to regulate certain standards, in accordance with needs, usability and the environment. environment and to produce transformers that lose as little energy as possible. In this way, the indicator is the care for the environment and the fact that the quality of transformer construction is taken in to account.