Pesa Acatus

Pesa Acatus (Latin for boat) is a standard-gauge electric multiple unit produced in a single copy at the Pesa plant in Bydgoszcz in 2006, specifically for the Marshal's Office of the Łódź Voivodeship. During test runs, it was a four-car unit (ED74 series, 16WE unit type, 310Ba+411Ba+411Bb+310Bb car type), and it is nowadays operated in a three-car configuration (ED59 series, 15WE type).

The design of the vehicle began in 2004, and a year later, it was offered in a tender and subsequently ordered. In April 2006, the production of the train was completed, and throughout that month, it underwent testing for approval for operation. On 29 May 2006, an official presentation of the unit took place in Łódź, combined with an inaugural ride. In 2011, the unit was withdrawn and awaited overhaul, which was ultimately carried out from December 2013 to June 2014. In 2016, the technically functional vehicle was withdrawn due to the expiration of its approval for operation.

In 2007, a development version of the vehicle named Bydgostia was created. In 2010, the manufacturer also built the Acatus II model, and in 2014, the Acatus Plus family, but they are only related to Acatus by name.

After World War II, electric multiple units were produced until 1997 exclusively by Pafawag in Wrocław. Pafawag was the manufacturer of the most popular electric multiple unit series in Poland, the EN57. After privatization in the 1990s, the plant ceased production of vehicles of this type, and the last produced unit was the ED73 in 1997. Polish State Railways then ended orders for new rolling stock, including electric multiple units.

Since the late 1980s, Polish State Railways, and since the early 21st century also local governments, mainly purchased diesel railcars and diesel multiple units, as fuel-consuming locomotives dominated the operation of non-electrified lines. This allowed Polish manufacturers and carriers to gain experience in the production and operation of lightweight rolling stock. Additionally, existing electric multiple units of the EN57 series owned by Polish carriers were modernized.

At the beginning of the 21st century, electric traction units from new manufacturers, such as Pesa Bydgoszcz, Newag, and Stadler, began to appear on Polish tracks. Pesa, after a deep restructuring in 1998, started producing railbuses in 2001, but in 2004, it also undertook the construction of the first electric multiple unit – the 13WE (EN95) for the Warsaw Commuter Railway, adapted to a 600 V DC. Despite plans to purchase 10 units of these vehicles, production was terminated after only one unit.

In 2005, the Marshal's Office of the Łódź Voivodeship announced a tender for the delivery of a three-car electric multiple unit. Newag and Pesa participated in the tender, and ultimately, Pesa's proposal was considered the most advantageous. This was the first order for an electric multiple unit from Pesa adapted to a 3000 V DC.

On 26 May 2005, a contract was signed for the delivery of the vehicle, which was to be completed by April 2006. Earlier, in 2004, work began on designing this unit. The task of developing a comprehensive concept for the unit was entrusted to the Marad Design studio. Marek Adamczewski [pl], Jacek Poćwiardowski, Jakub Gołębiewski, Mariusz Gorczyński, and Barbara Kusz-Hallmann were involved in the train's design. On September 6, the design team received technical specifications from the manufacturer, which were clarified, specified, and supplemented over the following months. On 4 February 2005, conceptual designs were presented, from which Pesa selected one for further development in April. Documentation, visualizations, and drawings were then created, with this stage completed by August. In September, Marad Design and Pesa presented the results of their work to the client after negotiations, and they began creating the final project. Work on the design was completed in November 2005, with final interior equipment arrangements made in February 2006. The body frame was manufactured in Sanok by Autosan.