Yes, I think it is correct that HART IS $2 billion short or $6 billion in the hole.
But GET monies comes only in small quarterly calendar  installments until the year 2027. 
For example, in the 1st quarter of 2015 the GET revenue was only $52 million but in  the 2nd quarter of 2015 the GET revenue was $65 million.
I believe that HART should not continue the rail project beyond the funding that the total quarterly GET monies as of 2027 can provide.