It will be interesting to see what the speed of the train was compared to the calculated maximum safe speed for that section of the line. Train speed limits are governed by a number of factors, the main ones being signalling method and requirements for Automatic Train Control/Automatic Train Stop. More often than not, the speed limit set in the timetable is lower than the maximum safe speed. There have been cases where trains entered a section of track at or just above the maximum safe speed and derailed due to the engineer's application of the train brakes in an attempt to control the speed. Uneven braking can cause the weight loading to shift just enough to allow a wheel to mount the rail, especially in a curve. Once a wheel mounts the rail, its all over.
As for making time, that's pretty common in the transit industry. It is safe so long as the you know where you can safely do it and under what conditions. Back in the bad old days when the Railway Post Office rode the rails, an engineer who could not make up lost time was looked down upon by his peers and management. More importantly, for every 30 minutes the mail was delayed the railroad company was fined $100. The two most famous train wrecks in American railroad folklore-the Wreck of the Old 97 and Casey Jones were actual wrecks. Both occured in the early 1900s (1903 and 1900), both involved engineers who were regarded as fast runners (Joseph Broady and John Luther "Casey" Jones) and both involved mail trains that were running about an hour late. Broady tried to make up time in the wrong place, came down the hill at Danville, Virginia too fast and derailed on a curved trestle. The entire train crew as well as several Railway Post Office employees and one Railway Express employee perished in the wreck. Jones had made up all but two minutes of the lost time but rear ended a stalled freight train at Vaughn's Siding, Mississippi. Based on testimony from his surviving fireman, Sim Webb, Jones was running about 70 mph most of the trip and was probably at or just above 50 mph when he rear ended the freight train due to the damage that resulted. Back in that day, this accident would have been noteworthy but not uncommon.
"When a man runs on railroads over half of his lifetime he is fit for nothing else-and at times he don't know that."