Western Railroad Discussion > Speed restriction on bulkhead flats

Back in the early 80s trains carrying bulkhead flats were restricted on the UP to 40 mph as they would 'fly' at higher speeds. Is this restriction currently in effect, and does it also cover centerbeam or 'opera window' flats?

I don't know if its due to the same reason, but bulkhead flats without constant contact side bearings are 45MPH on NS. Centerbeams and other flats are not restricted.

On the UP, yes, there are still speed restrictions in place for FB7 type bulkheads IF they don't have constant contact side bearings. Most of them have CCSBs though.

Ted S-P

As far as I know it still does, I haven't looked in the UP System Special Instructions in awhile.
Bulkheads ( FB car kind ) are 40mph
Centerbeams ( FI car kind ) are 50mph.

WOW! You guys are FAST! I figured I'd see a reply in a few hours but seven minutes must be a record. Thanks for answering so quickly and enriching my knowledge.

ISTR that the SP was a trail blazer in this. In the 1960s their R & D department determined that at speeds above 45 mph, the wind pressure on the rear bulkhead of an empty tended to lift the leading end of the car off the truck. Centerbeam cars are by construction heavier, so their "terminal speed" is probably higher, although by how much I don't know.

From the current UP SSI

Bulkhead flat cars:
• Loaded 50
• Empty cars equipped with constant contact side bearings 50
• Empty 40

Centerbeam flat cars:
• Loaded with plywood or lumber 60
• Loaded with other commodities 50
• Empty 50

The 50-ft "A" frame flats were the granddaddies of today's large centerbeam cars.

UP believed that, when empty, they behaved as bad or even worse than bulkhead flats. UP completely banned them. On the other hand, Milwaukee Road ran them.

Best regards,

Rob L.

I have personally attended to the cleanup of three derailments of empty BHF cars that were operated at speeds above 45 MPH.
And I was one of ten Division Engineers.
Apparently there were some educational impairment between the SP's research efforts and the execution by the engineers.

rob_l Wrote:
-------------------------------------------------------
> The 50-ft "A" frame flats were the granddaddies of
> today's large centerbeam cars.
>
> UP believed that, when empty, they behaved as bad
> or even worse than bulkhead flats. UP completely
> banned them. On the other hand, Milwaukee Road ran
> them.
>
> Best regards,
>
> Rob L.

That must have been hard on the Edward Hines Lumber Co who owned a fleet of A-frame flats and UP was the sole connection to the rest of the world. Explains why they sold the flats to Bennett Lumber Co.

Ted Curphey
Ontario, OR

Anyone got a picture of one of these A-frame flats? I don't think I've ever seen one before.

rob_l Wrote:
-------------------------------------------------------
> The 50-ft "A" frame flats were the granddaddies of
> today's large centerbeam cars.
>
> UP believed that, when empty, they behaved as bad
> or even worse than bulkhead flats. UP completely
> banned them. On the other hand, Milwaukee Road ran
> them.
>
> Best regards,
>
> Rob L.


Ha, ha, but look what happen to MILW trains every week.. derailed

rantoul Wrote:
-------------------------------------------------------
> What made these flat cars unreliable at higher
> speed?

There may have been other reasons, but the ones we on BN called flying flatcars had such a pronounced camber that at over 45 mph, they would generate enough lift for the car to rise to the point of the wheels not touching the track (note: the first Tacoma Narrows bridge was taken down in a 42 mph wind because of its aerodynamic characteristics).

I had an east man in at one of the sidings east of Yardley (Spokane WA), probably Otis Orchards. They were in for a light west man doing 60. When the west was by and the head man was back on the east, he told me that the west man had cars flying above the track. At the time, we never heard of such a thing. He didn't get car numbers but told me they were new 60 foot bulkhead flats. I told the west man to get slowed down and stop as gently as he could. They walked the train, found the cars, and found nothing wrong. They landed back on the rail.

The conductor on the west man gave me the car numbers and I turned it in. A while later, there was a General Order with some car number series, all new cars, limited to 45 mph.

TAW

Can somebody explain or show photos of "constant contact side bearings" for the rest of the story?