SJ Ma

Infobox Locomotive
name = Ma
powertype = Electric

---

size = 300px
caption = TGOJ Ma 405
builder = ASEA
builddate = 1953-60
totalproduction = 41
uicclass = Co'Co'
gauge = RailGauge|sg
wheeldiameter = 1,300 mm
length = 16,800 mm
height = 4,500 mm
weight = 104.4 tonnes
topspeed = 100 km/h
electricsystem = 15 kV 16⅔ Hz AC
collection method = Pantograph
poweroutput = 3,960 kW
tractiveeffort = 376 kN
railroad =
roadnumber =

Ma is an electric locomotive used by Statens Järnvägar and later other railways. 41 copies were built by ASEA between 1953 and 1960. It is derived from the older Mg-series, but unlike its predecessor it is used for freight and passenger trains. It is the loco that has been in use the longest in Sweden.

History

When the freight traffic on the Norrland lines was increasing towards the end of the 1940s, the need for more and stronger locomotives appeared. SJ decided to develop the Ma series based on the experience gained from the Mg series. Availability of more powerful motors made the locomotive capable of hauling heavy trains at 100 km/h, making the series quite flexible. Equipment was placed inside the locomotive, removing the noses and giving the Ma a very different appearance from the Mg series. ASEA delivered 32 locomotives to SJ, in addition to 9 to TGOJ. It was put into service on passenger and freight trains in Central and Northern Sweden.

When TGOJ got electric locomotives it also chose the Ma series. The nine locos were delivered from 1954 to 1958, and originally used on iron ore traffic between Ludvika and Oxelösund. They differ from the ones delivered to SJ with that they can be driven in multiple and have round instead of square side windows.

In the mid 1960s it was decided to modernize the Ma-series through rebuilding the drivers cabin and mounting new side windows, in addition to a number of technical improvements.

After the Rc locomotives were delivered in a large numbers to SJ in the early 1970s, the Ma series was restricted to freight only duties. This was despite being modernized at NOHAB in Trollhättan with changes to the bogies, main power switch, front lights and moving the cabin door to the centre to reduce noise. In 1991 SJ sold 25 of its 31 units to TGOJ, though they have not been used much. Two units are rented to BK Tåg while one has been sold to Inlandsgods.

External links

* [http://www.jarnvag.net/lokguide/Ma.asp Järnväg.net on Ma]