The House Appropriations Committee voted Wednesday to reject funding increases to Amtrak that would have gone toward infrastructure improvements. This comes just more than 12 hours after an Amtrak commuter train traveling on the busy corridor between Washington, D.C., and New York City, derailed in Philadelphia, killing at least 7 and injuring at least 200 people. The Republican-controlled committee said it would not provide new funding for Amtrak unless cuts were made in other parts of the budget to make up for increased spending.

How did the crash happen?

The investigation is ongoing. The National Transportation Safety Bureau (NTSB), a federal agency, is in Philadelphia and has recovered the train's black box, which records important information like a train's speed or the conductor's operation of the breaks. According to CNN, the NTSB will be looking closely at the train's speed, the condition of the tracks, the track's signals, and whether there was any human error.

Speed, in particular, will be important, CNN reported, due to the degree of damage to the train as well as the angles of the crash. One official told CNN that "the engine and two cars were left standing upright, three cars were tipped on their sides, and one was nearly flipped over on its roof. The seventh one was "'leaning hard.'"

What is Amtrak?

Amtrak is a public train service, funded with federal and state taxes, connecting major American cities. Congress spends about $1.4 billion a year on Amtrak. To put that in perspective, China, probably the most aggressive train builder in the world will spend $128 billion on rail in 2015, according to the National Journal.

Who likes Amtrak?

It's often the target of criticism from both sides of the aisle. Many conservatives point to the fact that Amtrak is not profitable and is not very reliable. National Journal reported this month that Amtrak's most reliable trains are only on time 75 percent of the time. Japan's trains, in contrast, are late "basically 0 percent of the time." For those reasons, Republicans see the service as a waste of money that's not even doing a great job of moving people. Pro-train people cite these statistics as examples of precisely why Amtrak needs more funding. They point to the increased demand for rail, particularly in the northeast, where Wednesday's crash occurred. Seventy-seven percent of the travel between Washington and New York is via the Acela train line. Pro-train people see this and argue that Americans want a reliable train service like those in Japan or in Europe.

America's transportation infrastructure is not good.

The debate about Amtrak also plays into concerns about the overall transportation infrastructure in the United States -- whether its highways or railways. As 60 Minutes' Steve Kroft reported last year, nearly 70,000 bridges in America -- 1 in 9 -- are considered "structurally deficient," which means they could be dangerous:

Where do we go next?

Because we're barely funding our transportation infrastructure enough to keep it viable, it seems unlikely that Amtrak or any other major public transportation project will be awarded serious investment by Congress.

That said, there are two interesting high-speed rail prospects at the state level. In California, its high-speed rail project is clinging to life, despite cost overruns and delays. When completed, officials say the train will take the trip from Los Angeles and San Francisco in less than three hours, with speeds of up to 200 MPH. The project broke ground in January. In Texas, a proposed privately funded high-speed rail system is shaking things up. It would connect Dallas and Houston with a 90-minute ride.