[6] Aside from being electric (EMU), the FLIRT is available in diesel-electric (DEMU), battery-electric, bi-mode EDMU, tri-mode diesel/overhead electric/battery (see also: Stadler WINK), and more recently hydrogen fuel cell versions.

Bi-mode models were first ordered by Italy's Aosta Valley region as (BTR.813),[7][8][9][10] then by Greater Anglia as the British Rail Class 755,[11][12][13] and Norske Tog.

The trains can have two to six sections and electric variants are available for all commonly used power supply systems (AC and DC) as well as standard and broad gauge.

All FLIRT variations use IGBT-based traction converters from ABB, which drive the TSA induction motors located in the two bogies at either end of the train.

The diesel, bi-mode electro-diesel, hybrid diesel-battery, battery, and hydrogen fuel cell versions are essentially baseline design with an additional non-passenger car inserted in the trainset – called a PowerPack car – which contains the electricity-generating and storage components, such as diesel engines and batteries, that provide electricity to the train to run off-wire.

In the TEXRail application, the diesel power module contains two 520 kilowatts (700 hp) Deutz AG TCD 16.0 V8 engines that comply with the US EPA Tier 4 emission standard.

[19] In November 2019, it was announced that Azərbaycan Dəmir Yolları (Azerbaijan Railways) had placed a €115 million order for ten Russian-gauge Stadler FLIRT units in various configurations, for delivery to begin in 2022.

[26] Two Stadler FLIRT units with an interior optimised for longer distance (EPm-class) were delivered to Belarus in 2015 to 2016,[27] and in January 2019, ten more of these trains were ordered for delivery in 2020.

On 9 October 2024, the local railway operator Lokaltog formally signed a contract for the supply of 14 two-car units of the battery–electric Akku model with an option for 10 more.

These trains will be partly manufactured in Switzerland with final assembly taking place in Poland and Belarus, and they are expected to enter service in spring 2026.

[41] The Cantus Verkehrsgesellschaft, a joint subsidiary of Hessische Landesbahn and Hamburger Hochbahn, became the first German FLIRT operator when they received their first train in 2006.

Since December 2007 Abellio Rail NRW has operated nine three-car and eight two-car FLIRT trains for regional routes between Essen, Hagen, Iserlohn and Siegen.

In 2006 DB Regio, a subsidiary of Deutsche Bahn ordered five five-section vehicles for regional services on the German east coast.

[44] On the InnoTrans 2008, a trade fair focused on rail transport, Vias announced their order for twelve four-section and seven three-section units.

[45] The same year, the Hessische Landesbahn (HLB) started to operate three three- and five six-car FLIRT units on the Frankfurt – Gießen – Siegen line.

[48] In June 2019, Transdev subsidiary NordWestBahn awarded Stadler a €100m order to supply 16 FLIRT electric multiple-units for the Bremen/Niedersachsen S-Bahn services.

[49] In July 2019, Schleswig-Holstein rail authority NAH.SH awarded Stadler a €600m order for 55 battery-powered FLIRT Akku multiple unit trains along with maintenance for 30 years.

The trains, which offer 150 km (93 mi) of battery range, were originally scheduled to enter operations in 2022 to replace DMUs on non-electrified routes.

[64] Ferrovie Emilia Romagna: Twelve units constructed with AnsaldoBreda: Stadler Rail will produce end units, traction systems and onboard auxiliary, end engines, while AnsaldoBreda will produce intermediate cars and handle final assembly and delivery to the operators at the plant in Pistoia.

[70][71] The very short delivery deadline (20 months), to meet capacity needs, allowed NS to invoke 'urgency mode' provisions in EU procurement rules and place the order without tendering.

These are similar to the FLIRT 3s owned by Greater Anglia in the UK but each will have an extra carriage for diesel generators in order to operate on tracks without electrification and as fully electric on electrified parts of the railway.

In total 14 trainsets of the bi-modal Class 76[80] will be delivered to serve Trønder Commuter Rail as well as the Meråker and Røros Lines.

All this is included in Bane Nor (Norway's Rail Management Agency) and Jernbaneverkets's plan to finally modernize the Trøndelag Railways, which have outdated buildings and infrastructure.

Łódzka Kolej Aglomeracyjna[84] (ŁKA) in 2012 ordered 20 two-car FLIRT3 units for service in the region around Łódź, for delivery by February 2015.

[86] In 2018 Koleje Mazowieckie started another order of total 61 five-car 3 kV DC FLIRT3 units (class ER160) in five batches slated for deliveries from 2020 to 2022.

They will consist of three aluminium car-bodies with a maximum capacity for 375 passengers, 214 of them seated, with one additional generator car in bimodal units[citation needed].

BLS ordered 58 six-car EMU sets in May 2017 for service on RegioExpress and Bern S-Bahn routes, with delivery scheduled to take place between 2021 and 2026.

On 9 June 2015 Trinity Metro signed a contract for the supply of eight four-car articulated FLIRT3 diesel-electric multiple units for the TEXRail commuter line, which opened in January 2019.

[112] In November 2019, the San Bernardino County Transportation Authority ordered an additional FLIRT powered via hydrogen fuel cell, the first such train in the United States.

[113] In September 2022, an order of four additional hydrogen-powered trains was announced by Stadler and CalSTA for Amtrak California inter-city services.