Belgian Railways Class 23
| Company type | Electric locomotive |
|---|---|
| Industry | Rail transport |
| Founded | 1953–1961 |
| Headquarters | Belgium |
| Products | Electric locomotives |
Class 23 locomotives belonged to SNCB’s fleet of electric engines developed during the 1950s, alongside Types 122 (later reclassified as 22), 123 (later 23), 125 (later 25 and 25.5), and 140 (also later 25 and 25.5). Constructed between 1953 and 1961, the total production included 50 units of Type 122, 83 of Type 123, 16 of Type 125, and 6 of Type 140, summing up to 155 locomotives. These machines served throughout Belgium on both freight and passenger routes until their decommissioning in 2012. Class 23 engines were capable of multiple-unit operation and frequently ran in pairs. All models shared identical traction motors and control systems, resulting in uniform power ratings.
The main distinction between Class 23 and Class 22 lay in their ventilation setup: Type 122 utilized roof-level grilles that were susceptible to water infiltration, whereas Class 23 incorporated three side grilles positioned low to reduce this risk. Additionally, six locomotives were outfitted with an extra vent located above the central grille on the side. Improvements also included increased chassis mass to boost tractive force and the adoption of regenerative braking technology, which allowed these units to manage heavy freight traffic on the Brussels-Luxembourg corridor.
Locomotive number 123.083 underwent extensive rebuilding starting in 1968, being redesignated as 124.001 and later renumbered to 2401 in 1971. This unit was equipped with a streamlined nose cone at one end, an ACEC Type G transmission featuring a modified gear ratio, and traction motors mounted with full suspension—part of an experimental project aimed at developing a four-voltage locomotive rated at . Although the multi-system initiative was eventually discontinued, this prototype contributed to the development of the Class 20 series introduced in late 1975. After completing high-speed trials reaching , it was reverted to its original configuration as unit 2383 in 1974 and subsequently operated in both freight and passenger capacities, earning recognition as "The Banker of Liège" for assisting trains on steep gradients around Liège-Guillemins.
Unit 2302 was distinctively modified by installing high-level ventilation grilles similar to those found on Classes 11, 12, 21, and 27, replacing its original openings with circular portholes—a design it retained until withdrawal.
The arrival of Class 18 locomotives in early 2012 initiated the gradual retirement of Class 23 units. By spring of that year, most had been withdrawn except for a handful kept for banking duties at Liège-Guillemins, which were soon replaced by Class 77 diesel locomotives.
Before January 1, 1971, these locomotives bore numbers from 123.001 through 123.083; following renumbering they were assigned new identifiers .
Unit number 2383 (previously known as 2401/124.001/123.083) is preserved by SNCB.