Would one be more common in normal operation?

It's a compound, so twice. But compounds normally had starting valves so they could route steam to all four cylinders when starting. Otherwise, until the first driver revolution there would be no steam for the front, low pressure cylinders.

So would the simple tractive effort basically be the “starting” tractive effort?

I’m sure I’m mixing up some terms here, just saw the two very different numbers listed for tractive effort and trying to understand them.

Correct. Here's the figures he's referring to:

Tractive effort
98,300 lbf (437.26 kN) (simple)
77,900 lbf (346.52 kN) (compound)

Factor of adh.
3.73 (simple)
4.7 (compound)

IIRC, the starting valve includes a pressure reducing valve, because full boiler pressure in those big front cylinders would cause the front engine to slip uncontrollably. However, it appears the design starting pressure is higher than the design running pressure on exhaust steam. Note the 3.73 factor of adhesion when starting. It seems the C&O had a lot of faith in sand.

A compound steam engine is an engine that uses the steam more than once. Compound engines are normal in ships.

For example, USS Texas (BB-35) has triple expansion engines meaning steam first goes to a small high pressure cylinder, then to a larger intermediate cylinder and finally to the largest low pressure cylinder. Texas actully has two low pressure cylinders per engine to divide the volume of low pressure steam. The size of each cylinder compensates for the reduced steam pressure available to it. This will use all the energy in the steam making the ship more efficient, increasing its range before refuelling.

http://battleshiptexas.info/images/Engi ... eRoom.html

Compound locomotives generally have two expansions. 1309 is a Mallet Compound meaning the rear cylinders under the boiler get boiler pressure steam froim the superheater, then exhaust it at a lower pressure to be used in the front cylinders, which are significantly greater in diameter. 1309's high pressure cylinders are 22" in diameter, the low pressure 35".

Most compound steam locomotives can be worked simple but the steam going to the low pressure cylinders has to be reduced in pressure to avoid overpowering the LP cylinders leading to either wild spinning of the drivers or a blown cylinder head which can be life-threatening to anyone in front of the engine.

Thus separate tractive efforts running simple or compound. The engines were intended to run as compounds.

Note that almost all modern steam locomotives have a compound appliance - the air pump.

Phil Mulligan

Thanks for all the answers! You learn something new everyday!

I'll add that this compound use of steam makes the 1309 a "true Mallet," as opposed to "simple articulateds" using the Mallet principle, such as N&W A 1218, or UP's 3985 or 4014. All those engines run on high pressure steam on all cylinders all the time, and and the cylinders are all the same size. This was more typical of later articulated engines, which were much faster than the compounds, or at least were normally supposed to be used in higher speed ranges. The cost was a comparative lack of efficiency with simple operation, and the maintenance of flexible steam joints that had to work under full boiler pressure rather than the reduced pressure used to deliver steam to the compound part of a true Mallet.

Something else that will be interesting when the 1309 goes into operation, especially if it gets to pull a nice, heavy train, will be the sound.

When starting in simple, the engine will sound like that, with two separate exhausts, like a simple articulated or a double header, with the two exhausts typically going in and out of synchronization, like two men hammering who sometimes pound in and out of unison. Then the engine will change to compound as speed increases; when that transition is completed, it will sound like a two cylinder engine, though the exhaust "note" might be relatively low or even mushy sounding due to the low exhaust pressure. Note that I am only talking about pitch, that low pressure exhaust can still be quite loud!

You can hear multiple starts on simple as a modern N&W 2-8-8-2 "true Mallet" does switching work at Waynesboro, Va. (sequence starts at 07:10), with a departure (starting at 14:12) where the locomotive changes to compound as it passes the microphones of the legendary photographer O. Winston Link and storms under the bridge of the C&O at the now demolished two level station there.

https://www.youtube.com/watch?v=UhBFD5JrKUE

There's a whole catalogue of simple and compound articulated sound here! An O Winston Link sound portrait of the helper operation between Boaz and Blue Ridge, Va., featuring Class A simple 2-6-6-4s and Class Y 2-8-8-2s. Some of these sounds were recorded trackside, and some from a caboose just ahead of the pusher 2-8-8-2.

https://www.youtube.com/watch?v=-LEjixDk5lg

Is it any wonder so many of us are enraptured by Link and main line coal country railroading, hooter whistles and all?

A glimpse of what that show up Blue Ridge looked like as well as sounded like:

https://www.youtube.com/watch?v=LF-6FKD0pr0

https://www.youtube.com/watch?v=zV8rA3UE-lc

In more “strange” news for this line, former Amtrak full dome “Ocean View” as well as a former Amtrak baggage car have arrived at the Western Maryland yards. Photos are available on other railfan sites.

An associate said "they do contract repairs, you know....."

Ocean View's status and future use:

https://www.railexco.com/railcar-leasing/

Glad they have their priorities in order :)

My curiosity was piqued by the Scenic railroad says pedal cars need FRA review article that "YeOldeEnjine" posted in the Railbikes thread.

I checked the schedule of the railbikes by first going to this page:
Rail Bike Tours in Frostburg, Maryland - A Unique Experience For All Ages & Abilities
I then clicked on the "Book Now" button, which let me see the "Frostburg Out and Back" (start times of 10:30 AM, 12:30 PM, 2:30 PM and 4:30 PM) and the "Cash Valley Road and Trolley" (start times of 10 am, 12 pm, 2 pm and 4 pm) tour options.

The Cash Valley tours start on May 21 and are offered thru October 31; the Frostburg Out and Back tours start on August 1 and is also offered thru October 31. The Railbikes operate 7-days a week from June 3 thru September 6.

Sounds like the county decided it would be fun to add the railbikes without understanding regulatory and safety requirements involved, and it sounds a lot like they didn't contact WMSR first. They'll need to work out some sort of temporal separation agreement, but that's not usually a good place to be for the RR, particularly when they need to operate that big engine as many days as they can fill seats to make some money for it's upkeep without railbikes being in the way (contractually and/or physically). County officials rarely have any concept of the rules of the road for operating a RR and they probably didn't give enough thought on putting little bugs in front of a very large and money-hungry windshield.