How many railroad workers does it take to operate a freight train? Fewer that you might think.

While car companies have been working to develop self-driving automobiles, the railroad industry has been deploying technology that may lead to self-driving trains.

Known as “positive train control,” this technology automatically slows, stops or diverts trains that are headed for a crash, much like a car’s automatic avoidance system does. The technology is still advancing, but autonomous trains — operating with no crew at all — may be rolling in the not too distant future.

Even before the arrival of positive train control technology, many railroads — including Amtrak — had downsized to one-person locomotive crews. (Amtrak trains, of course, have conductors and other passenger service workers on board.)

The prospect of more one-person crews, never mind self-driving trains, has generated controversy. Railroad unions in particular object, claiming that reduced crews put workers and the public at risk.

In Congress, Rep. Don Young, Alaska Republican, has introduced legislation to stop railroads from even thinking of reducing crew size. H.R. 1748, the Safe Freight Act, would require at least two crew members in the locomotive cab at all times. One would have to be a certified train engineer, the other a certified conductor. In addition, a regulation proposed in 2016 under President Obama by the Federal Railroad Administration would mandate two-member crews without any new legislation. The proposed rule is still pending at the Federal Railroad Administration under President Trump.

Despite the hand-wringing over one-member crews and calls for regulation, there is no evidence that these trains are any less safe than those with two-member teams. In its 2016 proposed rule, the Federal Railroad Commission acknowledged that it had no “reliable or conclusive statistical data” to suggest any safety issue with solo trains. In fact, they could be safer because distractions from others in the locomotive are eliminated.

But safety is not the real driver of the debate over crew size. At its core, this is a fight over protecting railroad jobs — nothing new for the industry that invented the term “featherbedding” and kept “firemen” and cabooses on trains long after either served any useful purpose.

Concerns about job preservation are understandable. The number of U.S. railway jobs has dropped precipitously over the past three-quarters of a century, from about 1.5 million just after World War II to barely 200,000 today.

But imposing new mandates on U.S. railroads is the wrong way to preserve jobs. The massive job losses in 20h century railroads resulted in large part from the top to bottom, comprehensive regulation imposed on the railroads. By the 1970s, just about every railroad had been in or near bankruptcy. Many thought the industry would disappear entirely. It recovered only after Congress enacted legislation in 1980 that reformed — and dramatically reduced — the regulatory burden on the train business.

A far better way of maintaining railroad employment is to let the railroads take full advantage of technological developments and other opportunities to improve the efficiency of their network. If they can do that, business will increase — allowing railroads to expand employment to meet the increased demand. Some specific jobs would still be lost, but the losses would be offset by overall growth among the firms.

Moreover, millions of people — including farmers, coal miners and steelworkers — in businesses that depend on affordable ground transportation for bulk goods would also benefit. As their shipping costs fall, their business improves, enabling them to expand job opportunities nationwide.

The idea of a train chugging across the country with only one crew member — or none at all — may strike some as inherently dangerous. But thanks to new traffic control technology, such lightly manned trains are safe, perhaps more so than today’s trains with crews. At the same time, the cost savings produced by these trains will benefit not just railroads, but also their workers and the rest of the economy.