Turkmenistan national railways Türkmendemirýollary has 4980 km of 1520mm track and is about to double that by the end of 2025. In 2019 they had 119 large diesel locomotives and over 10 000 wagons.

This is a shunter locomotive of the type CKD6E. Despite its huge size, this machine is not intended for long runs on open stretches of track but merely for shunting at shunting yards. The picture is not totally sharp as it has been taken from a moving car aiming at a moving locomotive. These machines have been built by the Chinese company CRRC's Ziyang factory.
Picture from Turkmenabat 13.9.2023 by Jaakko Riihimaa.

Turkmenistan national railways Türkmendemirýollary's passenger train locomotive CKD9A. It's a main line passenger train machine with a top speed of 120 km/h and a power rating of 3680 kW. Transmission is dieselelectric. They have been built by CRRC of China and have been sold to "Turkmenistan, Tajikistan and Mongolia etc.", not telling what the "etc" means. From 2004 to 2016, CRRC Ziyang delivered to Turkmenistan a total of 251 units of CKD9A and CKD9C locomotives. 25 of them were of the passenger train variant CKD-9A.
Public domain picture from an unknown place in Turkmenistan by Wikipedia user ILMur 2009.

Turkmenistan national railways cargo locomotive type CKD9C resembles the passenger train variant shown above, but the cargo machine is a 2x 6 axles double locomotive with a slower top speed of just 100 km/h and a continuous power rating of 2x 2430 kW in service.
Picture by the Wikipedia user "Bohndorf film team" 23.9.2015 from Ashgabat. The picture has been published under the Creative Commons CC-BY 4.0 license.