Underground railway
The capital cost, operation and maintenance of subway is high, year after year. Add erratic power supply, and various systems losses at different official levels. Note the mass created in London of 7/7 bombing. This is the age of terrorism; this factor should be visible in the concept paper. Japan can provide high-tech system, but the locals have to run it.
In the tropical countries, it is better and cheaper to go for elevated local train network in the first phase, (mass psychology also comes in); and then go for subway trains in the second phase (having completed the project homework). Uttara-Dhaka elevated train may be the first pilot project, for evaluation. Step by step--how far we have progressed in 34 years?
Simultaneously, we have to optimise the use of coal for power generation (we forgot abut it, like step parents, after we started using natural gas for several decades; plus the greenhouse effect cap by the industrialised nations, which the mighty USA continues to ignore). Solar power and lighting kits for the rural areas is not being publicised by the planners. Where is the local assembly plant?
We have to be careful about mega-tender paranoia.