Except the money, willpower and brains doesn't exist anymore in that country to build infrastructure like this.
I'd bet you anything they have approached the inner circle about sharing their existing subterranean shuttle network and they got knocked back. "It is more important that critical government staff have those trains for their own use in an emergency. You can't dual purpose those for military transport. Besides, they are very costly and where will the budget come from?"
They'll have to build new tunnels completely separate from the present ones to run these through and I bet you they won't tolerate them coming close to the existing web of rails for the elites to use. Also, they will costs trillions of dollars they are unwilling at this point to spend and take a decade of running those extremely expensive nuclear burrowing machines. I'd bet you it is getting tougher by the day to find people who know how to operate and maintain those machines.
That's why I think they won't get built. The Kwa is too broke and even if they had the money they lack the manhood for great building projects like this anymore.
Maybe they can just get Amrail to double task their coal car runs and strap the nukes on the caboose as additional cargo at bargain rates. That is the only option they could afford.