Being an ALCO fan for a very long time, I really like these locomotives. These Indian built YDM4 locomotives are a typical example of ALCO based locomotives used around the world. They were built by DLW (Diesel Locomotive Works) at Varanasi in India, which is wholly owned by Indian Railways.They were delivered as two slightly different models, some painted blue and white  and some red and white.  The blue 716-725 appear to have an extra 'cover' along the top of the long hood. (see below). I am not aware of why this is so. Locomotives 716-25 are generally used in the North and 701-715 are mainly seen in the south. If you check the photos closely there appear to be detail differences between the two types as well. e.g. location of the side grilles, lack of curved cover between the bogies on the red version. One source says that they were delivered between 1984-85 and 2001-2002. 25 were delivered numbered 701-725 Some Indian records state that no YDM4's were manufactured after 1990 (or1993), so could the last 10 (delivered in 2002) be second hand? The DSVN machines have builders plates showing 2002 for the last 10, so maybe not. The Vietnamese machines have the 'raised' cab roof, similar to those exported to Tanzania, but not present on Indian locomotives. The first batch painted red and white matched passenger cars also imported from India at the same time. It has been suggested that the locomotives and coaches were part of an assistance package from India.

Class	D13E
No. in Class	25
Manufacturer	DLW (Diesel Locomotive Works) Varanasi, India
Model	DL535A/RSD30 or YDM4 depending on who you talk to...
Gauge	1000 mm
Wheel Arrangement	A-1-A A-1-A/Co Co (References differ- Indian references clearly state Co-Co)
Road Numbers	701-708 (1983-84) Red and White / Builders # I6026-301-308 709-715 (1984-85) Red and White / Builders # I6026-341-347 716-725 (2001-2002) Blue and White/ Builders # 573 - 582
Weight	72 tonne
Length	14475 mm
Height	3535 mm
Width	3000 mm
Max. Speed	100 kph
Axle Load	12 tonne
Min. Radius	75 metres
Engine	DLW ALCO 251D-6 6 cylinder, 4 stroke inline
Power	1350 hp
Starting Tractive Effort	18935 kg
Transmission	DC-DC
Fuel	3000 litres

Steam Locomotives generally used the traditional French classification system. A steam locomotive with a 2-8-2 wheel arrangement is classified as 141 class, a locomotive with  4-6-2 wheel arrangement is classified as 231 class etc. Pretty straight forward, except what they did  if  two classes had a 2-8-2 wheel arrangement I'm not sure. It didn't happen so wasn't a problem?