Prototype Information: Wide Cabs

Today we talk about wide cab locomotives, and how that cab design came to be.  The earlies locomotives to have any sort of wide version of a cab were the early cowl units, such as the F45.  They had the basic shape of today's modern wide cabs, however, they did not include the structural support and safety of more modern wide cab locomotives.  Typically cowl units were found in passenger service.  Hood units, or freight locomotives, did not have any sort of wide cab until the DD40X.  Once again, that was a wide cab, but did not have the safety features of modern wide cabs.  It was actually exactly the same cab as was found on the F45, however it had been applied to a hood unit.

Modern wide cabs on locomotives began to develop with the Canadian National Railway.  They were designed from input from the locomotive crews, and then custom built for the railroad.  The first locomotives to receive these new cabs were GP38-2's.  Canadian National also ordered GP40-2's, GP40-2L's, and SD40-2's.  Since it was a Canadian railroad that first started using these cabs, they were often known as "Canadian Cabs."  In 1988, they became a standard option on new locomotives built by EMD, and today they are more often known either as "Safety Cabs" or simply "Wide Cabs."

Now wide cabs have become more of the industry standard in the last 20 years for several reasons, some more obvious than others.  The wider, higher cab gives the locomotive crew better visibility.  They sit higher up, the windows are bigger, and the nose of the locomotive is entirely below the level of the dashboard.  The view immediately in front of the locomotive, at ground level, is still nonexistent.  However the view to the sides and across the front of the locomotive is much better.  The wide cabs also give the crew more space.  The cabs are bigger, giving them more space to move around as needed inside.  With standard cab locomotives, the nose was higher in the center than on the sides, preventing the engineer from having good visibility off to the left, and giving the conductor the same problem off to the right. Also, the area directly in front of the engineer and in front of the conductor offered very little protection in the event of a collision.  The middle of the cab was sufficiently protected, due to the nose, but beyond the sides of the nose, the only protection was what a door and window could offer.

Less obviously from the exterior, wide cab locomotives offer much better crew protection in a collision than standard cab units.  The Federal Railroad Administration requires that wide cab locomotives have a skin of 3/8 inch armored steel with vertical reinforcements behind it.  The windshields are required to stop a .22 caliber bullet or a 24 pound cinder block, travelling at least 30 mph, without deflecting or puncturing at all on the back side of the glass.  All of this added reinforcement, in both the steel and the glass, makes the cab a safer place to be in the event of a collision.  The wider nose protects the entire width of the cab, and therefore completely protects crew sitting in the cab.  Wide cabs are standard on all new locomotives now.  Many rebuilt locomotives get them as well, when it is practical.  It gives the crew more space, and it puts more metal between them and any problems.

If you are interested in all the details of the FRA regulations governing cab construction and crew protection, you can look it up on their website: http://www.fra.dot.gov/pages/49.shtml.  I will warn you, it is very dry reading!  Also note that the links on this page will take you to images of what the link describes.  If there is anything else you are unfamiliar with, please let me know, and I will update the page accordingly.