Steam & Excursion > Steam and diesels together

Going over  my recently purchased Rio Grande's Pueblo Division Time-Table No. 8 I noticed a rule about using steam and diesel locomotives together. This time-table was issued on July 6, 1952 and covers sub-divisions 1-A and 1-B, the former Denver & Salt Lake Railroad. 
​  Here is the example.
​~ Except in an emergency L-131-132 class steam power will not be double-headed with a  three-unit or a four-unit diesel freight engine. It is permissible to double-head L-131-132 class engines with a  two-unit freight diesel engine, training the diesel engine ahead of the L-131-132 class engines.
​  The L-131 engines were numbered 3600-3609 and the L-132s were numbered beginning at 3610.
Here is another rule.
​~ Except as above restricted, diesel locomotives when double-headed with steam engines must be placed on head end, and will not be double-headed with steam engines smaller than M-64 class.

 

They didn't play well together?
 

Probably putting 4 units ahead of a 3600 put too much power on the head end of the train.  Putting the steam locomotives ahead of the diesels was to prevent the diesels from sucking hot steam exhaust into the radiators and engines.  They did the same "steam helper behind the road diesels" move down on the La Veta Pass too. 

4 units and a 2-8-8-2 probably developed too much tractive effort for the drawbars of the day.

Earlk Wrote:
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> Probably putting 4 units ahead of a 3600 put too
> much power on the head end of the train. 

I doubt a knuckle or drawbar could have handled that much tractive force.

This is a very interesting rule for a mountainous railroad during the transition period.

The 2-8-8-2's probably could stand more push, or buff forces on the front engine, than they could a straight pull. That and the front coupler didn't have a ny draft gear. Maybe that was what they were thinking.

Posted from Android

Another rule was one prohibiting two four-unit diesels on the front end of trains.



Edited 1 time(s). Last edit at 03/18/17 08:07 by Grande473.

Only saw two steam-diesel doubleheaders, one with an NKP 2-8-4
with a pair of GP's, and the other on the B&O with a 2-8-2 and an A-B
of FT's.  In both cases, steam was leading.

The restriction on the limit of power on La Veta Pass was account of the sharpness of the curves to limit the chance of causing a straight line derailment.

PlyWoody Wrote:
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> The restriction on the limit of power on La Veta
> Pass was account of the sharpness of the curves to
> limit the chance of causing a straight line
> derailment.

They had a whole different set of special instruction concerning the amount of trailing tons behind the henad end power and where to place in-train helpers.

> " to limit the chance of causing a straight line derailment....."

Another name commonly used was "string-lined derailment" .  Describing the effect of pulling a long surveys-string so tight that It no longer lies on the centerline of the curve, but has formed a geometric chord ---- a straight line, inside the curve,  connecting two points, being the shortest instance between those two points.
Typically seen with very heavy cars behind a string of empty flat cars, and too much strain applied at the headend.

A string-line derailment happened with a heavy main-line train, following a stop for a crew change, at the sharp wye tracks at the (NS)  Manassas, Virginia wye in the 1990s ------ the empty cars in the "string-line derailment" fetched-up against nearby, permanently-mounted, large, horizontal propane tanks ( for switch heaters) .

There was no disaster, but they permanently moved the crew change point further down the line, towards Catlett --- to where it is a straight track, for miles.

That sure was close.

W.
 



Edited 1 time(s). Last edit at 03/18/17 01:57 by wcamp1472.

And to think that UP had Big Boys up front with turbine power that would have been a sight to see.

Here are some more rules. Class L-131 and L-132 engines had a top speed of 45 mph. These engines were not allowed to double head with each other unless running light.  Class L-131 and L-132 engines, 3600-3619 were rated at 2,100 tons from  Denver to East Portal. In comparison 4-unit diesels 565-576 were rated at 3,600 tons.
​  When used in helper service out of North Yard to East Portal  engines 3600-3619 were to be placed 19 years ahead of the caboose. Extra diesel helpers would also be placed 19 cars ahead of the caboose.

While we at La Veta Pass, a little history:  April 11, 1903  Santa Fe New Mexican Newspaper
BROKE THE RECORD -- Extraordinary Run Made Over the Denver & Rio Grande Railroad.
A record breaking run which discounted previous mountain speed was made on the D&RG railroad over La Veta pass, from Alamosa to Pueblo on Thursday of this week, a distance of 133 miles.  Angus McBane of Omaha, Neb., while in Alamosa, received a telegram that his mother was at the point of death. He chartered an engine and a day coach with which to try to catch the train for the east from Pueblo.  The special was in charge of Conductor Young and Engineer Jones and made the run of 133 miles at a rate of 41 miles an hour.  Considering the heavy grade, crookedness of the road and the pass, the time is considerable remarkable.  Engineers of the road are ordered not to exceed 10 miles per hour in running over the pass.  McBane reached Pueblo 15 minutes before his train left for the east.