Here are two related facts:

1.  The MBTA proposed a package of fare hikes and service cuts yesterday, which could jack up subway fares by as much as 70 cents per ride.

2. There were major service issues on the Commuter Rail and Red Line today, due to “inclement weather,” or in other words, the cold. It seemed like half of my Twitter feed was stuck in Red Line hell this morning. (The MBTA’s Twitter feed, which listed all the delays, was pretty ugly itself.)

Now, forgive me because I’ve said this quite a few times before, but the reason service on the T is so bad is pretty simple: it’s broke. With a projected $161 million budget deficit this year and roughly $8.6 billion in debt, it doesn’t have enough money to fix the trains it has and it certainly can’t afford to buy the new ones it needs. Right now, there are $3 billion worth of backlogged maintenance problems in the system. Over 60 percent of Red Line cars are officially outdated — as in they’re so old they shouldn’t be running anymore — or will be within a year. It’s no wonder there were breakdowns this morning. When I was working on this story on all the troubles with the T, then MBTA GM and current Transportation Secretary Richard Davey explained to me how cold weather was murder on old trains. Put simply, when it’s cold out, there will be more breakdowns. That’s why I tweeted yesterday:

“Idle #MBTA thought: Nobody’s benefited more from this warm winter than the T. Old cars die when it gets really cold. Remember last year?”

Which brings us back to the proposed fare hike, which would be the T’s first since 2007. It’s no fun, but let’s face it, the MBTA needs the money. If you really want to know why service on T is so bad, it’s because for years we’ve put off really paying for the system, instead funding the thing with debt. It goes back to the disastrous “Forward Funding” plan the legislature put in place in 2000 to bankroll the system. The plan stipulated that the T would receive 20 percent of the state’s sales tax income to fund its operations.

Problem is, over the last decade, the state’s sales tax receipts have been much lower than expected (think about all the commerce that has migrated online, where you pay no sales tax). Rather than going back and making sure the MBTA had the money it needed, the legislature instead left the T shortchanged, causing it to borrow every year to close its budget deficits. The problem with that, though, is that all that borrowing has dramatically increased the debt service payments the MBTA has to make every year, always making the next year’s budget deficit even worse. You see this downward spiral we’re in, right? Right now, the T’s debt service payments are so high that the authority basically pays as much annually to cover its debt service as it takes in collecting fares from riders. Think about that for a second.

Really, the only solution for fixing the MBTA’s woes is a comprehensive overhaul by the legislature of the way the system is funded. In the meantime, though, you might bite your tongue before complaining about these new proposed fare hikes. I get that it’s frustrating to have to pay more for something that doesn’t work right now. And yeah, the MBTA hasn’t always been a picture of efficient operations. But those problems pale in comparison to the very fundamental flaws in the system set up to finance the MBTA. If you want to really know why T service is so bad, it’s because we were never willing to pay what it costs to run an on-time transportation system in the first place.