These were Vietnam's most powerful metre gauge steam locomotives. Mechanically they were very similar to the 231-501's with for example an interchangeable boiler.

The original version of this locomotive was built by Société Alsacienne de Construction Mecaniques (SACM) in France and delivered  between 1947 and 1950, before partition, so both North and South would have had examples after this time. According to "The Railways and Tramways of Viêt Nam", 27 were ordered. 

Trains Magazine lists 21 in the south in various states of repair in 1968/69. From 141-501 to 141-527. Locomotives 505, 506, 509, 513, 515 and 516 are not listed, the suggestion being that they may be in the north (or destroyed?).  A German report suggests that the order was never completed due to partition (and possibly the French withdrawal). The SACM machines can be distinguished by their smaller and squarer smoke deflectors. An initial order of 27 was delivered between 1948 and 1951 but in Tim Doling's book it is suggested that 508-512 never reached Indochina but instead went to the Congo. This doesn't  match the Train Magazine numbers, where 508, 510, 511 and 512 are listed as in the South in 1968. As the information in the Trains article comes from someone 'on the spot' in 1968 I am accepting it as correct. There is also a suggestion that a small number of 141's went to Cambodia after that country declared it's independence, but I don't know how many or which ones.

In 1951 a further 16 141s were ordered from SACM but because of the precarious political situation only 8 were delivered, numbered 141-A-101 to 108 .

Mr Doling in his book states that in 1955 in  North  Vietnam there were only 10 141 class Mikados. As at least 21 141-500's were still in the south does this mean that most were 141-A-101's? There is a colour screen grab of 141-A-102 in the north probably in 1954 after the country was divided.

J.D.H. Smith lists the 141-A-101 machines as belonging to the Yunnan railway so were they purchased initially for that line?

It's interesting to note that in the Trains Magazine article that while 21 141-500 locomotives are listed in various states of disrepair, no A-101 locomotives are listed as in the south in 1968 so did they all end up in the north after 1954?
  In 1964-5 the Northern system built  two locomotives from French spare parts and scrapped locomotives known as Tu Luc or 'self-reliant'. The first, 121 was named 'Nguyen Van Troi' after a revolutionary martyr and was handed over on 18 December 1964,  and the second was numbered 122 and it possibly still exists.  The locomotives were built at the Gia Lam Works, Hanoi. A third locomotive was planned but never built. Because of the increasing intensity of the war, production was moved to a safer place, China.

The final version was built by  Tanshang Works  in China for the Northern system from 1965 to 1974 and totalled 67 units. The Chinese locomotives were copies of the Tu Luc locomotives which were a direct copy of the earlier French machines, but a bit lighter.They had steel fireboxes instead of the French brass ones.The Chinese copies were classified ZL class (Zi Li 'unaided' or 'self help (self reliant?)) by the Chinese manufacturers.

It's interesting to note that at about the same time the US was delivering the 'BB' 907 class (later D9E) diesels to the South.

The German report states that the following locomotives were noted as still in operation or still in existance in 1988/89:

SACM: 141-102,103,105,106,107,108,109,110,115 (were these all renumbered 141-500s or a mixture of 141-500s and A-101s?

Gia Lam: 141-122

Tangshang: 141 - 151,152,153,155,156,157,158,159,162,164,165,166,167,
168,172,174,176,177,178,179,180,182,183,185,186,187,188,189,190,
191,193,196,197,198,199,200,202,203,204,208,209,210,211,212,213,214,215,216

The German report suggests that there were in fact 66 'ZL' type Chinese built locomotives numbered 151 to 216 but classifies them as SY2 not ZL.

From 'trains-worldexpresses.com':
Among the French built engines taken over in 1976 from the Regie des Chemins de fer du Viet-nam, mainly classes 231 (4-6-2) and 141 (2-8-2) the 141-101 to 110 sometimes still hauled the passenger train Ha Noi - Sai Gon as far as Vinh until 1992. 141-121 and 122 had been built at Gia Lam, and other ones, numbered from 141-151, by China (class SY2).
This suggests that there were 10 141's inherited from the Southern system after 1975 (101-110).
So the Chinese built 141s are classified as SY2 by China in this document as well. Even more puzzling is the following:
"The GP6 class was a lightweight version of the Chinese JF class locomotive; while the SY2 was based on the Chinese SY class locomotives with a Belpaire firebox, teardrop-shaped smoke deflectors, and other changes". No mention of the French origin of this locomotive. As the Chinese SY class was based on an earlier ALCO supplied locomotive I really doubt this.

So this doesn't make sense as the ZLs were clearly a copy of the SACM 141s so I really doubt the SY2 references. My research so far has failed to come up with any reference to an SY2 class. The German author seems to be confusing the 141's with the Chinese standard gauge SY class.

It would seem that in later years the remaining 141's were confined to the north, probably because of the plentiful supply of coal. It would appear that the last 141's operated until about 2002.

Tim Doling lists the following 141's as still in existance:

141-122 (Tu Luc) Gia Lam Works (awaiting restoration)
141-158 Sai Gon Station (static display)
141-159 Gia Lam Works (undergoing restoration)
141-165 Gia Lam Works (undergoing restoration)
141-179 Vinh Station (static display)
141-182 Di An Works (static display)
141-190 Di An Works (undergoing restoration)
141-206 Da Nang Station (static display)

It's a pity that none of the original SACM built locomotives seem to have survived.

There has been talk of the listed locomotives being restored for several years, but this doesn't seem to have happened yet.