The survey is being conducted by a third party auditor engaged by IRCTC, an official said.
More than 200 trains are pitted against one another to get top rating as the 'cleanest train' in the fleet of the national transporter, in a first of its kind cleanliness survey of trains undertaken by railways.
A similar survey was conducted on railway stations all over the country in 2016 as part of the government's Swachch Bharat Abhiyan.
A total of 475 rakes of these 210 trains are to be audited out of which 386 rakes have already been surveyed.
The survey is being conducted by a third party auditor engaged by IRCTC, an official said.
"Such independent survey on cleanliness of important trains will be carried out every year and is expected to bring a sense of pride and competition among the zonal railways and maintenance depots. The survey of trains is expected to be completed in a couple of months," an official said.
The assessment heads will include checking on board facilities - condition of toilets, equipment, tools, manpower, vestibules, doorways, dustbin, linen, pest management, watering, waste management, on board housekeeping staff and on arrival at stations.
Each category has points assigned to it with the highest priority given to the condition of toilets.
The checking starts right before the trains start their journey till the arrival at the destination station.
The survey will be conducted both based on passenger feedback and audit.
This is the third such survey initiated by railways to maintain cleanliness in the railway network.
The first survey was conducted by IRCTC in 2016 by conducting interviews of passengers at the stations on various parameters of cleanliness and rating them on this basis.
The second survey has been conducted by the Quality Council of India (QCI) who with the help of their partners has conducted the survey of 407 major railway stations (75 A1 category and 332 A category stations) of Indian Railways.
The next survey report for cleanliness is expected by QCI for stations in the month of July, 2018.