Since its delivery, most of the trains are still being tested and undergoing final assessments, before being used on regular services on Line 3 of the Manila Metro Rail Transit System.

[1] These trains are the first LRVs produced by CNR Dalian, which caused some controversy due to compatibility issues raised by MRTC.

[12] The CRRC Dalian 8MLB LRVs are owned by the Philippine government and operated by the Department of Transportation (DOTr).

With the ridership of the Line 3 already peaking at almost half of its 350,000 original daily capacity, there have been calls to purchase additional trains as early as 2008.

[13] Initially, in February 2013, the government was looking at buying 52 second-hand trains from Madrid Metro and Inekon Trams to immediately augment the problem,[14][15] but after evaluation, the plan was dropped in June due to less advantage and higher maintenance costs.

[16] The first of three contracts of the Line 3 capacity expansion project, which involves the procurement of 48 light rail vehicles,[17] was opened for bidding on February 22, 2013.

The first prototype, LRV 3101, arrived at the Port of Manila on August 14, 2015,[21] and was assembled at the LRT-1 Baclaran Depot on September 3.

[4] As of the present, none of the 3100 class trains are in operational service, primarily as a consequence of restrictions outlined in the maintenance contract established by Sumitomo.

Additionally, a legal dispute involving the Department of Transportation (DOTr) and the Metro Rail Transit Corporation (MRTC) has contributed to the non-operational status of these trains.

[36] In September 2024, The Department of Transportation (DOTr) said that it aims to deploy the China-made Dalian trains on the MRT-3 line by the middle of 2025 after years of being idle.

[37] The car body is made of stainless steel with a livery of sky blue and yellow fascia.

[1] After the contract for the procurement of the 48 light rail vehicles was awarded to CNR Dalian in January 2014, controversies arose.

A Regional Trial Court in Makati issued a temporary restraining order on January 30 after Metro Rail Transit Holdings (MRTH), the majority shareholder of the Metro Rail Transit Corporation (MRTC), filed a case against the DOTC, citing violations with the build-lease-transfer agreement between the Department of Transportation and Communications (later the Department of Transportation) and the MRTC.

[48][49] Rolf Bieri, a consultant with former maintenance provider Comm Builders & Technology Philippines (CB&T), said in a Senate hearing on February 20, 2018, that the trains are within the allowable specifications set by the DOTr.

[5] An audit from TÜV Rheinland revealed that the weight of the trains under fully loaded condition complied with the specification limit.