चलती है (ग्वालियर-भोपाल वाया गुना बीना ICE) उड़ती है धूल जलते है दुश्मन खिलते है फूल - Adi Singh

SL disagreements are because of internal security concerns and not because of cost concerns, I think. The Tamils of Sri Lanka (mainly residing in the northern part of the country), if both countries are connected by train, get easy access to India as well as Indian Tamils, which is a concern for the Sinhalese majority country. That is the main reason why the northern part of Sri Lanka is mostly under connected and under developed to the southern part. They don't want an easy and affordable connection between the Tamil people on both sides of the ocean.

---