Rostov can forget subway. In a instagram live broadcast Deputy Prime Minister and recently appointed curator of the Southern Federal District Marat Khusnullin said better to build tram lines in cities with a population of 1 million-plus than costly subways.

This is in big rostov website.

https://big-rostov.ru/vice-premer-marat-xusnullin-postavil-krest-na-rostovskom-metro/

This puts end to excuses like "weak soil" etc.

Khusnullin's talk is reiteration of what he said before already.  In Is Russia abandoning the 'subway for cities over 1 million people' doctrine? I wrote: Is Russia abandoning the 'subway for cities over 1 million people' doctrine? Inherited from Soviet times, when population of a Russian city exceeds 1 million people, that city qualifies for a subway system. Plans are prepared and implementation starts. With this doctrine, there are subways that have been built in the past i Russia : Moscow, St. Petersburg, Kazan, Yekaterinburg, Nizhny Novgorod, Novosibirsk and Samara. Gazeta.ru write that this doctrine may be abandoned now. Gazeta.ru write Deputy Prime Minister of the Russian Federation Marat Khusnullin, said to President Vladimir Putin "it is not practical to build subways for cities over 1 million people". Deputy PM says in the future Russia must rely on railroads for cities over a million people, instead of subways. Subways are simply too expensive.

In a TV interview from his car, Khusnullin said already planned started subway projects for three cities will be finished. Lucky cities are Chelyabinsk, Krasnoyarsk and Novgorod. Certainly big cities of Moscow, Saint Petersburg continue to have their subway investments.

https://youtu.be/N2ei8adQxn4