Co-Co Diesel Electric
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.
Above: Builders plate on 724 clearly showing December 2002 as the build date.
Click on thumbnails for fullsize image
Images of D13E 717
Above: Drawing of YDM4 - second version
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?
Diesel locomotives have a completely dfferent clasification system.
All diesel classes start with the letter 'D' (for diesel?) then a number which I believe is related to the locomotives power output. The third character defines Electric' (E) or hydraulic (H).
e.g. D5H class = Diesel + 500 hp + hydraulic.
Again, what happens if two classes are the same I don't know.
I am still investigating pre 1975 classifications. Some are the same e.g. 141 steam class, and some are different e.g. 'BB' class instead of D9E.
Railways in Vietnam
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