Bo-Bo Diesel Hydraulic
These small Russian built diesel hydraulics formed the main non steam roster for a number of years, though they are getting old and worn. At 400 hp they are hardly the most powerful locomotives ever built but seem to have served their purpose extremely well.
They are referred to as type TU7E (the E designating export) by the Russians and are very similar to locomotives supplied to Cuba for it's metre gauge system.
There seems to be some confusion as to how many are still in service. One source says none are now in service! (definitely not true!)
According to one source, the locomotives were introduced from 1975 onwards. Another source says they were built from 1972 to 1994 but not introduced to VN until 1984 (This seems to be reasonably accurate - see further sources below). 183 locomotives were still in service in 2001.
The original TU7's were built for Russia's narrow gauge lines including forest products lines. They were introduced in 1971/2 and were built by the Kambarka Engineering Works. This was the seventh model in a line of narrow gauge locomotives stretching back to the 1950's. There were two models, the TU7 and TU7A. It would apear that the DSVN vesion is the heavier TU7. The TU7 was designed to be used on any gauge from 750 mm to 1435 mm.
The company had already supplied up to 30 TU5 locomotives to North Vietnam (see TU5 page).
A Russian language source states:
There were 247 TU7s delivered to Vietnam in 1985. They were classified as TU7E and TU7AE.
In Vietnam they were classified D4H (Diesel, 400hp, hydraulic transmission)
They were numbered in the D4H-400 and D4H-500 (192 TU7E), and D4H-800 (62 TU7AE) ranges.
Due to poor mechanical condition 50 had been withdrawn by 1998.
A small number were converted to standard gauge (1435 mm) and classified as D4Hr class.
From Another Russian Language Source:
In 1986 The TU7 (TU7E) was modified with "slightly modified circuitry, increased static deflection spring suspension, friction dampers used in place of hydraulic vibration" and was classified as TU7A (TU7AE). This suggests that the last batch of 62 (TU7AE) D4H-8XX, were delivered during or after 1986. The same source also says: "Another batch of TU7 on 1000mm track was built in 1991 for the railways of Vietnam". Could this be the TU7AEs?
Verified Road Numbers from Whiteboard Image
(There is a photograph of a depot whiteboard on the Vietnam Railways Forum showing various locomotive classes and their availability)
Click on thumbnails for original images
D4H at Da Lat July 2010
The following images of D4H-528 were taken by myself at Dalat Station Tuesday 27 July, 2010
D4H (TU7E) 2452 at Thap Cham August 2010
I captured the following images at Thap Cham Tuesday August 5, 2010
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 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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