This is the second oldest locomotive in Catalonia still in operation and one of the five oldest in Spain. The MZA company commissioned ten small locomotives for shunting in the depots and port facilities of the Mediterranean area, which formed the 600 series. They were built in Belgium by the Société Anonyme de Marcinelle & Couillet in 1886. At that time, they were modern machines with a Belpaire firebox and Walschaerts valve gear, rocking-type safety valves, with a boiler pressure of 9 kg/cm², developing a power of 288 hp and a tractive effort of 2,891 kg.
These were the only locomotives acquired by MZA for this specific purpose, remaining for almost eighty years in virtually the same geographic locations where they were originally assigned. When RENFE was established in 1941, the new company numbered them 020-0231 to 0240, and they continued to perform the same functions for which they were intended. The locomotive we have at the Móra la Nova Railway Museum, 020-0236, MZA 606, continued to perform shunting duties at the Poble Nou de Barcelona depot, the port, and the Estació de França until the mid-1960s. In the early 1970s, it went to Barberà del Vallès, where Ciba Especialidades Químicas S.l. placed it at the entrance of its factory until, at the end of 2004, it became the property of the Museum of Science and Technology of Terrassa. This institution, in turn, loaned it to the Vilanova i la Geltrú Railway Museum until, in March 2019, MNACTEC signed an agreement for its transfer to the Móra la Nova Railway Museum, where it finally arrived on April 29, 2019. Over two years, APPFI volunteers have dismantled and repaired the small locomotive to be able to have it smoking and running again on the tracks of the old riverside depot, after being stopped for sixty years. In October 2021, the boiler received certification from Industry for its operability. The restoration and commissioning were made possible through a crowdfunding campaign in which 176 supporters of our Museum participated.
Regarding the name "Cuco" – as they were known among railway workers – there are many different stories. One even suggests the nickname came from France. It's also unclear which group of locomotives they were given to, whether to the MZA ones or those of the Central of Aragon, which had a very similar appearance and characteristics. However, it seems the former were the ones who received this moniker, due to the scandal caused by their safety valves when they were triggered. This produced a sound reminiscent of the song of the *Cuculus canorus* bird, better known as the common cuckoo.
Technical data sheet
| Any construction | 1885 |
| Constructor | Société Anonyme de Marcinelle & Couillet (Belgium) |
| Factory number | 791 |
| Track width | 1674 mm. |
| Company Name Origin | Compañía de los Ferrocarriles de Madrid a Zaragoza y a Alicante (MZA) / RENFE |
| Previous serial number | 606/020-0236 |
| Locomotive length | 6.422 millimeters. |
| Empty locomotive train | 14.920 kg. |
| Locomotive rated power | 288 hp |
| Maximum speed (km/h) | 45 |
| Axis layout | 0-2-0 T |
| Combustible | charcoal |
| Fuel capacity | 500 kg. |
| Water capacity | 2,200 liters. |
Client: FPPFI
Restoration Types: Functional
Any: 2021
