TORONTO - An investigation over a deadly Via train derailment west of Toronto has revived calls for automated safeguards that could take over in a crisis and reduce the risk of potentially fatal mistakes.

A computerized system called positive train control drew national attention last week after transportation advocates suggested it could have kept train 92 from careening off the tracks in Burlington, Ont.

While there's no doubt automation has cut down on transportation-related deaths, experts warn no computer -- no matter how sophisticated -- can guarantee passenger safety.

And in some cases, they say, the growing dependence on technology can cause human operators to panic when the system fails -- sometimes with catastrophic results.

"There's no such thing as no risk," said Alexandre De Barros, an expert on intelligent transportation systems at the University of Calgary.

"There are always things you can do to improve safety... but you can never do away with humans and human error."

Automated controls meant to reduce human missteps have long been integrated into planes, trains and ships, and researchers continue to develop new technologies to take over a wider range of functions.

Underwater sensors connected to a dynamic positioning system are designed to keep ships on course and out of dangerously shallow waters.

Aircraft typically stay on autopilot -- technology invented nearly a century ago -- for all but a few minutes of each flight, an advance that safety experts link to a steady drop in fatal plane crashes.

Even early locomotives had systems to keep engineers alert by forcing them to press a button at the sound of a bell or other signal, said David Jeanes of Transport Action, a non-profit advocacy group in Ottawa. On some trains, a lack of response would trigger the brakes, he said.

Some have argued the Burlington derailment could have been avoided if the train had been better equipped.

Investigators with the Transportation Safety Board found the train was travelling at four times the speed limit when it jumped off the tracks over a switch, despite several warning signals.

An additional safety measure called positive train control would have allowed others to override the engineers and remotely stop the train once it missed the signals.

Still, every system has its limits, Jeanes said.

Positive train control won't keep locomotives from smashing into vehicles or people at rail crossings -- among the most common types of railway deaths, he said.

And technology can fail or be turned off, Jeanes notes, pointing to the Costa Concordia disaster that killed at least 25 people in January.

The cruise ship carrying some 4,000 people ran aground off the coast of Italy after sailing too close to an island. The captain later admitted he had shut off the alarm for the vessel's computer navigation system.

Meanwhile, aviation experts have sounded the alarm over the industry's automation addiction and how it affects pilots' ability to fly without a technological safety net.

An Air France crash that killed 228 people in 2009 shows the tragic consequences when pilots can't handle the loss of computerized flight controls.

Flight AF447 from Rio de Janeiro to Paris plunged into the Atlantic after ice blocked the airspeed sensors, shutting down the autopilot system, investigators found. Mistakes made by a junior pilot then caused the aircraft to stall.

"Because the system is so automated... pilots aren't normally trained for that kind of situation," De Barros said.

That doesn't mean technological safeguards should be scrapped, Jeanes said, adding the benefits still outweigh the pitfalls.

"If someone runs a red light, you don't blame the technology," he said.

Automation is only likely to increase in coming years, experts say, with the transportation industry currently focusing its efforts on cars.

Though cruise control has been around since the 1940s, cars have largely dodged the automation craze.

Researchers are working to develop cars that drive themselves using sensors to detect objects around them. Cars that take the guesswork out of tricky parking manoeuvres have already hit the market.