Steam & Excursion > What does it take to make a steam locomotive fully bidirectional?

Somebody came to me the other day with pics of bidirectional steam locomotives that were used in commuter service on the Boston and Albany. 

Questions immediately came up as to why 99 percent of the world's steam engines were NOT bidirectional. What is involved with doing this?

Spent hundreds of miles pulling passenger trains tender first at mainline speeds with multiple stops.  What would help is:
cut away tender sides to enhance visibility.  
Perhaps a swivel seat to. Improve comfort running backwards.
 Insure the trailing truck on the engine is appropriate for leading the engine in reverse.  
2-8-0s and 4-6-0 are not good choices for reverse mainline speeds.

Best engine I ran in reverse was a 2-8-2 tank engine.  The trip was about 25 miles one way and we had to maintain the schedule of electric emu.  This tank would dig right in and off to the races.   Nice on the return trip with just a bunker to see over/around.  Of course no smoke or cinders.  The limiting factor is the water capacity.

So to make a good bidirectional engine,  make it oil fired,  keep the tender, low and narrow.  With a good trailing tr



Edited 1 time(s). Last edit at 09/06/25 13:00 by Tominde.

Tominde Wrote:
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> So to make a good bidirectional engine,  make it
> oil fired,  keep the tender, low and narrow.
>  With a good trailing tr

Or get a Beyer-Garratt, they were designed to go both ways.

On nearly all steam locomotives with a pilot truck, there is a 'centering beam' under there that comes back to the first axle and is tied in to the frame to actually do something by equlizing the suspension, guiding it.  Or, a centering design on the pillar spring on the pilot deck that does the same function that literally forces it to center so it is actually guiding the locomotive and not just there for the ride.

The trailing truck doesn't have that on most, just carrying the weight of the firebox.  But Baldwin, etc., did this extensively on some locomotives that knew they would be running typically in reverse a lot, specifically logging rod engines with a trailing truck - the 2-8-2's, 2-6-2's, etc.    Could be done, was a deliberate design feature.

Not only that, but I found evidence that there was some steam that could not reverse around the same curvature they came through in forward - namely, the PRR K4s, in a clearance diagram note, which is why 1361 kept derailing in the 1987 operations while being wyed.   It was the angle of attack on the flanges and the suspension of the trailing truck.

But throwing this all to the wind, we have 1309 backing down the hill every day it runs from Frostburg due to the turntable approach problem.   It's safe enough, but the concern was on the flange wear on the rear driver pair.   That's what I've seen in the field on operations that are running in reverse a lot - where it 'gets you' is flange wear on the rear drivers unless there's a trailing truck designed to help.   Some operations have added flange lubricators to deal with that, because dropping an axle and profiling wheels (or renewing tires) can be a major undertaking.



Edited 1 time(s). Last edit at 09/10/25 07:16 by randgust.