In the early 1950s, the Comboios de Portugal saw the need to quickly convert the existing steam locomotives to other types of propulsion due to the lack of coal. The series 0300 railcars, of which 25 were built in 1954 and 1955, played a role in the changeover. They came from the Royal Dutch Factory for Furniture and Railway Vehicles Allan in Rotterdam, which earned them the nicknames “Allan” and “Holandesa”. The vehicles were equipped with two British AEC diesel engines, each delivering 220 hp, which transmitted their power to all four axles diesel-electrically.

The railcars had two cabs and could be used alone or in double. Per vehicle there were 24 first class seats, 50 second class seats and up to 34 standing places. There were no control cars, but one or two trailers could be coupled between two railcars. The vehicles were widely used and were equipped with new engines from the French company Poyaud in 1981 and 1982. 21 examples were converted to the series 0350 in 2000.

Around the turn of the millennium, there was an urgent need for new multiple units on the Portuguese railways, since the existing vehicles were several decades old and, above all, contributed to a bad image. On the other hand, there was a poor financial situation, which made it impossible to procure a sufficient number of completely new vehicles. When analyzing the existing multiple units, it was noticeable that the 22 surviving examples of the series 0300 were structurally still in good condition and the engines had only been renewed in the 1980s, but the external appearance and interior fittings were very outdated and growing passenger dissatisfaction.

Thus, 21 train sets were fundamentally rebuilt in 1999 and 2000, giving them a completely new appearance and extending their service life by another 15 years. The conversion was carried out by the Empresa de Manutenção de Equipamento Ferroviário, which roughly translates to “company for the maintenance of railway material” and is based in Lisbon. New features included air conditioning, larger double-glazed windows and automatic doors. The first class compartment was left out and there were now 64 seats available. However, the engine power, which was lower than that of the old engines, soon led to the vehicles being phased out. Four were still in use in 2017 and two in March 2019.

In addition to the diesel-electric railcars of the 0300 series, diesel-hydraulic vehicles of the 0400 series were procured from 1965. These vehicles were manufactured in Portugal and were soon also called “Rolls Royce” because of the manufacturer of the engines. One power car and one control car were coupled, with the motor car having two engines. These powered one axle of each bogie via a hydraulic transmission. 

Although all 19 vehicles were later converted to the 0450 series, modernization took place in 1994 and 1995. The installation of new Volvo engines was planned, but ultimately only the interior was revised. Wooden partitions were now made of glass to improve the sense of space. Upholstery, trim and lighting have been updated and a toilet has been removed to make more room.

Like the 0350 series, the 0450 series arose from the fact that the CP needed a large number of new diesel multiple units for the non-electrified routes, but could not afford to buy completely new ones. The 0400 series had been modernized a few years earlier, but as the changes only focused on the passenger compartment, there was still a need for modern technical equipment. For this reason, all 19 examples were converted into the 0450 series from 1999, whereby nothing was taken over from the old vehicles apart from the basic structure of the car bodies and the wheel sets.

With new Cummins engines, the engine power increased and at the same time the top speed was increased to 120 km/h. An electronic diagnosis system was developed, which provided the driver with important information at all times. Passengers could now enjoy individual seats, air conditioning and an electronic passenger information system. Over time, the 0450 series was also able to displace vehicles from the 0350 series, even if the latter looks visually more modern. Some are even used in intercity traffic.

To save the construction costs of new electric multiple units, the Portuguese Railways decided to rebuild older vehicles of the series 2100, 2150 and 2200. Between 2003 and 2005, 57 sets were brought to EMEF, where they were modernized and got new bogies with traction motors from Alstom. This created the series 2240 that consisted of three cars per set of which the central one was powered on all axles. Most of the time they are being used for commuter and suburban traffic, but sometimes also for intercity services.

The RENFE series 102 and 112 are high-speed trains, which are referred to as “Talgo 350” due to the design speed of 350 km/h. The power cars are derived from the ICE 1 and were built by Adtranz/Bombardier. Due to their special, aerodynamically optimized shape, they were nicknamed “El Pato” (the duck). The coaches are derived from the Talgo 7 and each have a single-axle bogie with passive tilting technology between two cars.

The first series of 16 sets was delivered between 2000 and 2004. They have twelve coaches with seats in three classes and a bar car. There are several kitchens scattered throughout the train. Between 2008 and 2010, 30 additional sets were delivered, which have a larger number of seats thanks to only two classes and one less kitchen. Due to these changes, these sets were designated series 112.

The CAF Oaris is a high speed train designed for a top speed of 350 km/h (217 mph) that originated in the AVI 2015 program funded by the Spanish state. It is being offered with four and eight cars and each car has two 660 kW traction motors in one bogie. It can operate under 25 kV AC and 3 kV DC, while its platform is also capable of 15 kV AC and 1.5 kV DC. The prototype was built for standard gauge, but was also designed to use either broad gauge or even variable gauge bogies. 

The prototype was tested from 2011 as RENFE class 105 and also reached the envisaged speed of 350 km/h. However, no orders were placed by RENFE. The only customer by now is the Norwegian Flytoget AS which ordered eight Oaris in 2015. Although planned for introduction in 2018, they were only fully ready for service in 2023. They also took part in the tender for Britain's high speed line HS2, but ultimately the design jointly developed by Alstom and Hitachi won.

The series 120 and 121 comprise a total of 57 four-car multiple units for fast regional transport. The special feature is that the trains can be re-gauged between the standard gauge and the Iberian broad gauge within a minute. On the new standard-gauge lines with 25 kV AC they reach 250 km/h with an output of 4,000 kW and on the broad-gauge lines under 3,000 V DC the top speed is limited to 220 km/h with 2,700 kW. The 29 trains of the series 121 differ from the series 120 in that there is no first class and no cafeteria.