SGR is a commercial enterprise, its suppose to make money. A toll road would be comparable to SGR. SGR at the very least should be cash flow positive i.e it should be self sustaining. Without government support the SGR would collapse, even after government mandate to use it, it still can't service its loans. Kenya pipeline, Kenya ports and KAA are all profitable owned by government.
There's tacit effort to sanitize Jubilee 1st term when all the decisions that have adversely affected the economy were made. From SGR, medical, Turkana oil, Gulana, universal electricity connections, misappropriation of Euro bonds etc.
The projects that were undertaken haven't resulted in increased economic activity that would result in increased tax revenue. Other than the initial tick in GDP e.g SGR increased G.D.P by an estimate of 1.5% during construction.