To be fair, the reporter isn't exactly wrong.
Usually the railways look at the cost of 'procuring electrical power', irrespective of the source of the electricity, when talking about costs and savings. And since EOG based electrical power is costlier than HOG based electrical power, it would be cheaper to use HOG. We tend to think of electricity bill as the money we pay to the providers, but in this context, it is just the cost of procuring the electrical power, irrespective of the source.
On a related note, HOG also saves...
more... money compared to self-generating rakes, having lower electricity costs.