The Série 1800 was a class of 10 diesel-electric locomotives built for the Portuguese Railways (CP) in 1968. Designed and engineered by English Electric, they were closely modelled on the British Rail Class 50^[1] locomotives but built for CP's 1,668 mm (5 ft 5+21⁄32 in) Iberian gauge and larger loading gauge than possible in Great Britain.

Class 1800 locomotive number 1805 in 2009

Type and origin Power type Diesel-electric Designer English Electric Build date 1968

Specifications Configuration: ​  • Commonwealth Co+Co Gauge 1,668 mm (5 ft 5+21⁄32 in) Iberian gauge Axle load 18.5 long tons (18.8 t; 20.7 short tons) Loco weight 110 long tons (111.8 t; 123.2 short tons) Fuel type Diesel Fuel capacity 1,000 imp gal (4,500 L) Prime mover English Electric 16CSVT Mk II RPM: ​  • RPM idle 450 rpm  • Maximum RPM 850 rpm Engine type four stroke, four valves per cylinder Aspiration turbocharged, intercooled Generator EE822/16J Traction motors EE548 Cylinders V16 Cylinder size 10 in × 12 in (254 mm × 305 mm) MU working 110V, stepless electro-pneumatic throttle Loco brake Air, dynamic Train brakes Vacuum

Performance figures Maximum speed 87 miles per hour (140 km/h) Power output 2,700 hp (2,000 kW) gross, 2,500 hp (1,900 kW) net Tractive effort: ​  • Starting 57,320 lbf (255.0 kN)  • Continuous 38,800 lbf (172.6 kN) at 19 mph (30 km/h)

Career Operators Comboios de Portugal Class Série 1800 Locale Portugal Withdrawn 2001 Disposition 1 preserved, 9 scrapped

Like the British Rail Class 50s, they were equipped with an English Electric 16 CSVT engine and produced 2700 hp. Unlike the Class 50 locomotives, which made extensive use of electronic control, the Portuguese locomotives were equipped with conventional control gear. The main generator and the traction motors were identical to those used on the BR Type 3 and Deltic locomotives. The Série 1800 locomotives were built to be closely compatible with the smaller CP Série 1400 (themselves based on the British Rail Class 20) and also to use as many common components as possible. When delivered they were the only diesel locomotives in Portugal authorised to run at 140 km/h (87 mph).

By mid-1969, the class had logged more than 4 million kilometres in regular use and had proven their worth by hauling heavier and faster trains than other locomotive classes for CP.^[1][2]

Initially they were used on the express services on the main line between Barreiro (near Lisbon) and Faro. After the electrification of the main line the locomotives were relegated to Inter Regional services in the Algarve. They were also used on the steeply-graded Beira Alta line, but were displaced by the more powerful Série 1960 locomotives in the late 1970s.

Apart from one which suffered serious accident damage, the Série 1800s were all withdrawn in 2001.

A single example is now part of the CP Railway Museum collection and has been repainted into the original blue livery. All others have been or are being scrapped (as of late 2012/early 2013).