KES Class A
| Industry | Tramway operation |
|---|---|
| Founded | 1892 |
| Headquarters | Oslo , Norway |
| Products | Class A trams and trailers |
Class A (Norwegian: Type A) comprised twenty-one motorized trams and twelve trailers constructed by Allgemeine Elektrizitäts Gesellschaft (AEG) alongside P. Herbrand & Cie. for Kristiania Elektriske Sporvei (KES), intended for operation on the Oslo Tramway in Norway. These vehicles measured approximately 6.4 by 2 meters (21 ft 0 in by 6 ft 7 in), featuring a wooden body with an enclosed cabin and open platform sections. Each tram accommodated sixteen seated passengers and twelve standing. The twin-axle motor cars were powered by two AEG NB80 motors, with eighteen units producing 24 kilowatts (32 hp) and three delivering 36 kilowatts (48 hp) of power. Additionally, one tram was manufactured through collaboration between Norsk Elektrisk and Skabo Jernbanevognfabrikk.
The initial delivery included eleven motor trams and seven trailers, arriving in time for the commencement of service on 2 March 1894. Later that year, four more motor units were added in December, followed by two additional trams in 1897. The unit from Norsk Elektrisk was acquired in 1897, with the three higher-powered trams arriving the subsequent year. The final set of trailers was procured in 1899. Starting in 1910, the fleet size was deemed insufficient, prompting reconstruction of motor cars into trailers. From 1917 onward, further modifications combined pairs of trailers into larger units. While the original trailers remained operational until 1936, the enlarged versions continued service until 1949. One motorized tram preserved in its initial form remains today.
History
Established in 1892, Kristiania Elektriske Sporvei became Oslo’s second tram operator, tasked primarily with building the Briskeby and Skøyen Lines. The company invited bids for a comprehensive electrical system, receiving six proposals. Ultimately, KES selected Berlin-based Allgemeine Elektrizitäts Gesellschaft (AEG) to supply not only the trams but also the power infrastructure and overhead wiring. As part of this arrangement, AEG acquired a majority stake in KES.[1] This installation marked AEG’s sixth tramway project and still involved considerable experimentation.[2]
The tram bodies were produced by P. Herbrand & Cie. in Cologne, utilizing electrical equipment from AEG and chassis supplied by Bergische Stahlindustri. The first batch—eleven trams numbered 1 through 11 and seven trailers numbered 12 through 18—arrived before the line’s official opening on 2 March 1894. Due to higher-than-expected demand, KES quickly ordered additional units, receiving four more motor cars in December numbered 19 to 22.[3]
Concurrently, Norwegian manufacturer Norsk Elektrisk sought entry into the tram market and collaborated with Skabo to build a vehicle matching Class A’s specifications, completed in 1895. Although KES initially refused to test this tram due to contractual exclusivity with AEG, Norsk Elektrisk conducted trials on private tracks. Subsequently, KES leveraged this situation to secure two extra trams originally destined for the Straßburg Tramway; these were instead allocated to Oslo as numbers 23 and 24.[4]
In early 1897, Norwegian investors took control of AEG’s stake in KES, prompting renewed cooperation with Norsk Elektrisk and eventual purchase of their tram unit in May that year. In September, Norsk Elektrisk organized a competition on the Holmenkollen Line between an AEG tram, their own NEA model, and Holmenkolbanen's Class 1898 tram. The AEG vehicle prevailed with an average speed of 17.3 km/h (10.7 mph) and energy consumption of 0.40 kW per tonne; Holmenkolbanen's tram followed closely at 16.7 kilometres per hour (10.4 mph) using 0.38 kW/t; while NEA finished last at 16.5 kilometres per hour (10.3 mph) with consumption of 0.36 kW/t.[5]
Around this period, all units underwent modifications to regulate power via resistance control, streamlining operation processes. The last three trams delivered in 1898 (numbers 18–20) featured this system from inception and were equipped with more powerful motors.[6] Additionally, KES acquired five trailers from Herbrand numbered between 41 and 45.[7]
By 1899 KES began integrating newer Class U trams into service. To avoid numbering conflicts with competitor Kristiania Sporveisselskap (KSS), all trams were renumbered starting from 101 in 1902.[8] Larger Class SS trams arrived beginning in 1909; due to their size advantage, Class A units were increasingly considered undersized and from 1910 many motor cars were converted into trailers. Original trailers lacked braking systems initially but these were installed between 1912 and 1914 alongside wheelbase extensions.[9] The last motorized Class A vehicles were withdrawn following the 1914 Jubilee Exhibition. Tram no. 102 was retained unmodified as a shunting vehicle before being preserved as a heritage piece in 1919; it was restored to its original configuration and is now exhibited at the Norwegian Museum of Science and Technology.[10]
Starting in 1917, pairs of modified trailers were dismantled and recombined to form larger units—ten such vehicles numbered from 356 to 365 emerged initially serving the Lilleaker Line. Following the merger of KES with KSS into Oslo Sporveier in 1924, these ex-motor trailers were renumbered between 474 and 483 under the new company banner and remained active until their retirement coinciding with closures of the Korsvoll and Rodeløkka Lines in 1949. Scrapping occurred between April 1951 and March 1952.[11]
The original trailers saw limited use after 1914, primarily operating as secondary trailers behind Class SS trams. Declining passenger numbers from late-1920s onward led to retirement of two units in 1930; remaining original trailers were phased out between 1932 and 1936 during fleet rationalization efforts focusing on eliminating smaller trailers.[12]
Specifications
The trams shared largely uniform specifications, with minor differences among certain units. All vehicles were painted green and measured approximately 6.4 by 2.0 meters (21 ft 0 in by 6 ft 7 in), except for units 118 through 120, which extended to 6.50 meters (21 ft 4 in) in length. Each tram featured an open bay platform capped with roofs at both ends, along with a central cabin containing benches arranged longitudinally. The cabin was initially fitted with five equally sized windows on each side; this was later modified to a three-window configuration arranged in a long–short–long sequence. Constructed with a wooden frame, the interiors were lined with thin iron sheets. Seating capacity accommodated 16 passengers, with standing room for an additional 12, besides the motorman and conductor. Every unit weighed in at 6 tonnes. The trams rested on twin axles, possessing a wheelbase of 155 centimeters (5 ft 1 in) and wheels measuring 845 millimeters (33.3 in) in diameter. Originally equipped with skirts, these were promptly removed due to operational complications.[13]
Except for numbers 117 to 120, all trams were outfitted with two AEG NB80 motors, each delivering 12 kilowatts (16 hp), resulting in a total power output of 24 kilowatts (32 hp). Units 118 to 120 came equipped with the more robust VNB120 motors, each rated at 18 kilowatts (24 hp), combining for 36 kilowatts (48 hp) total power. Both motor types were bipolar serial direct current motors configured as compound motors, enabling speed control by adjusting three spools between series and shunt connections across seven preset switches. Additional controls included reverse operation and emergency braking switches. Electrical power was drawn via a trolley pole. All units featured clamp brake systems for routine use and incorporated dynamic braking through short-circuiting for emergencies.[13]
Tram number 117 was a prototype constructed by Skabo, fitted with motors from Norsk Elektrisk & Brown Boveri. It matched the dimensions and overall design of the other trams but utilized two NEA1 motors rated at 12 kilowatts (16 hp) each.[13]
The earliest trailers matched the motorized trams in size, consisting of cabins measuring approximately 4.2-meter (13 ft 9 in) in length and seating for 16 passengers. Without the need for a motorman’s space, they could accommodate up to 18 standing passengers. The second generation trailers extended to an overall length of 7.2 meters (23 ft 7 in), featuring cabins about 4.5-meter (14 ft 9 in) long. Unlike the first series’ longitudinal bench seating, these later trailers offered seating arranged two plus one abreast, with seats facing each other.[14]