Class S4 Specifications:
Locomotive Class: S4
Manufactured Country: Germany
Manufactured Company: MAN Diesel Company
Imported Year: 1962
Type of Locomotive: Diesel Hydraulic
Prime Mover: MAN V12 L12V21
Maximum Power: 1000hp – 1500RPM
Maximum Speed: 80kmph
Axel Arrangement: B-B
Weight: 47 Tons (Power car only)
Length: 59 Feet (Power car)
Colour: Dark Red
No. of Units Imported: 5
Locomotive Numbers: 621-625
These sets were imported in 1962 & these are very similar to Class S3 DMU as Class S4 is also a product of MAN Diesel Company which supplied S3 sets. As usual only the power car was imported & coaches & dummy cabs were made by locals.
Sri Lanka received all five Class S4 sets under USAID Fund Program. The main difference between S3 & S4 is the Class S4 Prime mover had Super Charger technology. Apart from some minor technological differences these are similar to S3 DMUs’.
This DMU also ran up to Nanu-oya on the main line. Because S4 had more power than S3 we can think that Class S4 was successful than S3 on the up country line. These had been used for office trains also.
To control the overheating of the engine of S4, SLR took steps to make new ventilators on the body. However all S4s’ were withdrawn from the service around 1990. Therefore the service period of this DMU can be stated as just above 25 years. All 5 of them were scrapped.
Credits to Gehan Chandika & Nipuna Dodanthenna.