The development at the turn of the century of the internal combustion engine, both petrol and diesel powered, led to the rise of wheeled road vehicles which were to revolutionise road transport.
Until World War I, steam-powered vehicles were still commonly in use for road travel. Experiments with the combustion engine were also making headway on the railways, at the same time as trials for using the other great invention of those years, the electric motor.
In the 1920s, Ferrovie Nord experimented with a petrol coach supplied by BREDA and, later, with other types of vehicles, with the aim of replacing steam power in certain situations.
This included trialling a rail bus solution, using a small coach from Carrozzeria Varesina on an OM chassis, fitted with railway wheels instead of road wheels and with non-steering front wheels.
The BREDA railcar was not a great success, and in 1937 it was transformed into a service vehicle by fitting the top with a platform for maintenance of the electric line, which was being extended to other routes following the Milano-Saronno and Bovisa-Meda lines. The rail buses were also short-lived.
In the 1930s, a pair of single-cab diesel railways supplied by OM of Milan arrived, which frequently replaced traditional trains at less busy times between Como and Varese or Como and Saronno.
The lines which FNM focused on for motor traction were mainly those with fewer passengers and bumpier routes, where the small diesel railcars had the advantage over the classic trains with steam locomotive and traditional carriages.
Towards the end of the 1930s, FNM decided to further develop motor traction on lines that were not yet electrified or with little traffic. Three bogie diesel railcars therefore arrived from BREDA, similar to the Aln 556 being supplied to Ferrovie dello Stato.
The need for internal combustion railcars came to an end with the completion of electrification, and the BREDA railcars were sold on to Ferrovia Centrale Umbra.
The 1960s saw a renewal of the need for internal combustion traction on the FNM network, but this time in order to solve a different issue. It was needed to replace the old steam locomotives, now near to being permanently withdrawn, for the shunting of freight wagons and passenger coaches, particularly at the Librera (Bovisa) yard and the Piazzale Cadorna yard. In addition, there was still one non-electrified line left, the Castellanza-Castiglione Olona, which served the paper mills and companies still present in the Valle Olona. The goods trains on that line were pulled by steam traction with the old 270 locomotives.
After several trials carried out in the 1950s with some test machines, in 1967 FNM hired, and later purchased, two small two-axle diesel-electric shunting locomotives built by TIBB. These were used mainly for shunting passenger coaches in the non-electrified shunting yard at Cadorna Station. Of these two DE 510s, one still exists at the MILS museum.
Between 1971 and 1974, 5 new locomotives built by TIBB arrived. These were diesel-electric bogie locomotives which took over pulling goods trains on the Valle Olona line until it was closed down.
These locomotives subsequently continued shunting services in non-electrified locations and, following the decommissioning of the electric line, also on the Saronno-Seregno line and industrial sidings. One DE 500 is scheduled to be preserved as a historic vehicle.
In the mid ‘90s FNM purchased 18 large electric diesels second-hand from the Czech railway, still in existence today; mainly to tackle the new demands of its Cargo division but also used as needed on its own company network.