In July 2004 the Slovenian National Railways ordered 20 three-tension locomotives by Siemens Transportation Systems. Originally, delivery was planned for the June 2006 till March 2008, but in June 2006 it was rescheduled so that the last machine, 541 110, already could be introduced in May 2007. The 541 series is being used for both (international) freight and passenger services.

The Siemens official press release included a preliminary artist impression of the looks of the new 541 series, at that time, except for its logos, identical to that of the OBB 1216 series (see image above). Technically spoken both series are identical, representing the at that time newest ES64U4 platform.

All 20 machines were assembled in the Siemens factories in Munchen-Allach. In February 2005, the very first frame was welded together and completed under works number 21159. Until October 2005 Siemens worked on this machine, being fifth member of the new ES64U4 family, after completing the 1216 001, 002, 003 and 050 earlier that year. When leaving the factory the machine was painted red with a grey frame, slightly brighter than the OBB machines, and numbered 541-101. On its frame, all relevant inscriptions were applied, like a complete UIC number and the sub type designation ES64U4-VF.

In November 2005 the 541 101 was transported to the test tracks of Velim (CZ), guided by Re 474 010. In the mean time, Siemens had started series production in Munchen, starting with the future 541-001, representative of the second sub type, ES64U4-VB2.

The 541s mix and migle a lot with their Austrian brothers and sisters in everyday practice.

Until 13.12.2005 the 541 101 remained naked, then logos, and additional striping were applied. The cabin rooftops were covered with gray adhesives. In the first months of 2006 the 541 101 went on test runs in Austria together with 1216 141 and on 13.03.2006 the engine even visited Holland! This proves that these machines, although not configured to do so in regular service, can function under 1,5kV DC voltage systems, as it also ran on small track sections part of the Dutch conventional network. The engine made some promotional runs at the HSL that day.

Mid June 2006 the first engine, again 541-101, was officially handed over to the Slovenian Railways, per 27.07.2006 immediately followed by 541-001. As serie delivery was continued with the ´normal´ VB2 subtype engines (001-010) the 101 kept on travelling through Europe in order to get the approvals for the countries the subtype VF should be present later on. For the 541.1 sub serie, also homologation for Italy is planned, requiring an additional RFI service number, which will be E190 101-110 for this serie.

On May 13th the first series was completed with the delivery of SZ 541 110. One remarkable fact during the delivery was 541 107 visiting Luxembourg at the end of March 2007. Before this machine was sent to Slovenia it ran in Luxembourg, testing 25kV installations.

In February 2008, SZ 541-101 started trials in Croatia, to get final approval for this country.

In May 2008, SZ 541-109 visited Hungary, to perform trials by the GySEV.