Problem is Kenyans are always trying to reinvent the wheel. A massive country like the usa discovered long ago that there's only so much you can move by trucks. Look at public transport in Nairobi, we are always struggling with half measures while cities like Tokyo move millions efficiently by rail every day.
By the way, even as we build the SGR, why don't we improve the existing railway network? Imagine if they used just a fraction of that money to buy modern passenger trains, employ competent staff and and ran the stations on a 24 hour basis.