Steam & Excursion > Train Line Steam Pressure

Back in the days when passenger equipment was steam heated what was the steam pressure sent back through the train?  I remember a little steam venting at the rear of the train and I'm sure this was to allow steam to freely flow throughout the length of the train and carry along with it any collecting condensate and vent that at the last car/end of the run.  Each car I'm sure drew steam off the top of the main, used it for heat in the radiation (fin tube element?) and then discharged the condensate out the steam traps and onto the roadbed. 
It doesn't take a lot of pressure to heat as the heat energy is rejected in the radiation element as the steam goes through the change of state and condenses, giving up something like 960 BTUH per pound, and a lot of older high rise buildings in major cities, such as Chicago, could heat the building with 5 psi pressure or less.
I remember seeing in the cab of the Burlington Route Hudson displayed in Galesburg a steam pressure reducing valve on the side of the boiler in the cab in front of the fireman to reduce the pressure being sent to the train but I've never learned what that steam pressure was.  
I'm sure too back in the day coach yards and stations were equipped with steam connections to keep the trains heated - coach yards before the consists were moved to the station and stations before the power was placed on the train and the steam fitters made the connection between the tender and first car.  I remember a Burlington Route steam fantrip originating in Chicago Union Station back in March or April 1963 behind Class O5b 4-8-4 #5632.  After boarding the train and finding a seat we walked to the head end and 5632 must have recently been coupled to the excursion consist because I vividly remember a steam fitter between the tender and baggage car making the steam connection.  I'm sure the blue flag had been hung but was too young at the time to know about that.  
Thanks all,
Sierra Western  

It seems to me that when we run the Holiday Express with the 4449 we’re putting somewhere between 50 and 100 lbs into train, which is only 6 cars and it’s usually not all that cold outside. I could see it needing a lot more than that with more cars and colder weather.

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Found this in The Denver and Rio Grande Western Railroad Rules and Instructions Governing Operation, Inspection and Maintenance of Air Brake and Communicating Signal Systems
Heating, Lighting and Air Conditioning of Passenger Train Cars  Operation of Locomotives  Handling of Trains  Effective September 10, 1977.

82-D Steam pressure on standard gauge passenger trains should be regulated on a basis of 50 lbs. for the first car and 10 lbs. for each additional car up to a maximum of 140 lbs.  When necessary to increase the above pressures to insure proper operation of steam generator on diesel locomotives, it is permissible to do so.

Scott is correct. The carmen will call the locomotive and ask for various pressures depending on the amount of heat they need to keep the cars warm. Much less on a sunny afternoon run than a cold day or night run.

Use of live steam or exhaust steam for car heating was introduced in 1878.  Prior to that coal stoves were used in each car, with uneven distribution of heat in that car and risk of fire in a wreck.

Freestanding water heaters, such as the very widely used Baker Heater, provided more even heat throughout the car and reduced fire hazard, and could be used as a heat exchanger with steam supplied from the engine.  See sketch below.  Such heaters could be lighted to keep a car from freezing when set out or othewise separated from a steam source.

My textbook on steam heating states "The less pressure at which the heater can be operated, the better."  Remember, car heating is not pressure operated, but rather is a heat transfer device.  All you have to do is keep steam moving throughout the system to exhaust at the tail of the last car, and the entire supply pipe will be at least 212 degrees.  The heat in each car can be regulated by a regulator valve on that car.  The Air Brake Association suggested a setting of the regulator on the locomotive at 5 psi per car.  My CB&Q rulebook suggests 10 per car.

Cab equipment consists of a globe valve, a pressure regulator, and a gauge, under control of the fireman.  It's a 2" [Edit: or 2 1/2"] pipe on the left of the backhead near the firemans right hand when seated.  He would adjust the regulator, not the globe valve, when necessary.

There were vapor systems (live steam piping throughout the car) or water circulation systems on each car.  Water systems used a closed loop of water piping, an expansion tank on or near the roof, and a Baker Heater (or similar) used as a heat exchanger.

I couldn't find it this morning, but I've got rulebooks which include a list of signals to be used on the train signal line by the conductor which includes something like "increase heat" or "decrease heat", if steam is not reaching the last car.

-LD

 



Edited 2 time(s). Last edit at 10/30/20 13:34 by LarryDoyle.

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And, don't forget that steam could also be used in the summer for air conditioning.

-LD

LarryDoyle Wrote:
-------------------------------------------------------
> And, don't forget that steam could also be used in
> the summer for air conditioning.
>
> -LD

If you cars equipped with Steam Ejector Air Conditioning.

LarryDoyle Wrote:
-------------------------------------------------------
> I couldn't find it this morning, but I've got rulebooks which include a list of signals
> to be used on the train signal line by the conductor which includes something like
> "increase heat" or "decrease heat", if steam is not reaching the last car.

From the 1939 edition of "The Consolidated Code of Transportation Rules and General Instructions":

Rule 16.  Communicating Signals
16(j)   o o o o o o   When running — increase train heat.
16(k)  o o o o o o o   Shut off steam heat.

Not many folks are familiar with the way the ' communicating air whistle'
was arranged.

So let's start ar the basics ...
There is a sharp shrill whistle in the loco cab that sounds when activated.
The loco and cars are filled with a pressurized air signal line from the loco throoutgh
every car in the passenger fleet, including 'all "head end" cars, like baggage cars,
express mail cars,RPOs, etc.  

in order to 'work' all locos ( double headers, etc)  must be fitted with air signal lines----
so that things like steam heat pressure, station stops can be requested,  & can be controlled.

The air signal system, at the loco,  has a small air tank, that sends a blast of air to the cab whistle,
when the signal cord at a car vestibule is is pulled and released.  A short blast in the cab
will be heard.  The signal train line is pressurized when used, and the cab whistle sounds
with each pull of the vestibule signal cord at the cars.

Signalling using the system requires slow, deliberate, distinct yanks of the signal cord.
with long trains, it can take like 10 seconds or more to propagate the pressure
changes all the way to the loco cab ---+for one toot.   That's why often the engineer will
acknowledge the cab signal's message with two confirming toots of the
engine's whistle..

Often times, on a double-header, the engine closest to the train will supply and operate
the steam heat coordination.   It's common that the cab-signal whistles, if equipped,  in each loco
cab will sound when activated by the conductor's whistle cord in the train vestibules.

Many times helper engines are added to get over steep grades.  Since the main loco
remains attached to the train, there is not a need to interrupt the flow of steam heat,
when adding or removing helpers; thus, freight engines can be used, even though
they may not be fitted with the communicating air lines or the cab whistles.

The main concern with shutting off the steam heat flowing through the train is
the SAFETY OF THE CAR INSPECTORS .   When cars are to be added or 
removed from a passenger run at  a 'through stop", or a terminal, the steam heat
rigid  connectors  between cars, locos, etc, must be manually knocked apart.
To safely perform this disconnect operations, the steam pressure and the heat must
subside, before staring the separation.  Train crews, of trains under way, are familiar
with the preparation steps needed  before they arrive at the station where the. couplings
are to be manipulated

Breaking-open steam connections with pressurized steam is extremely dangerous 
when you're cramped between and under the train.... The steam line must be vented
and pressure depleted.  Two things are VITAL to both 'be accomplished' before
separating steam lines of a train during a through-stop where cars are to be shifted.

While rolling along, First, the steam flowing from the engine must be shut OFF in the loco cab, and then
the trainman,at the rear of the train must open car shut-off valve in the rear vestibule
of the last coach of the train  --- to vent ALL the steam pressure out of the steam heat
lines.

The venting process is done about 10 to 15 minutes before the expected station stop.
The series of short whistle blasts, from the conductor's cord, relayed in the loco cab,
while underway, tells the engine crew to turn OFF the steam flow. ( see the code,
explained in the earlier post)
 
Once the steam in the cab is shut off, the engineers  may use the loco whistle
( two blasts, while follow g along) to confirm that the heat-flow is turned off.

Crews are often well used-to routine station stops and car additions, so that both the
engine crew and the train crew do the 'steam heat ballet' as a regular routine of daily
runs, without a lot of use of the awkward air signal system.

The trainman at the rear of the cars, opens and vents the steam line,  leaving the end valve
open --- until set to the "venting position",  by the car inspectors prior,  to departure and resuming the run.

The end valves MUST be slightly open and venting steam continuously. while the 
steam lines are cionnected.  If not open , water from the condensed steam heat will
collect in the steam piping --- from the rear of the train, and will progress from the rear, forward.

In sub-freezing weather, condensed steam, water,  freezes very rapidly... the open vent at the 
rear of the train is a VITAL necessity....to keeping all the piping hot, and gently blowing.

The communicating whistle and it signals ensure that the steam is flowing properly from the cab,
and I'd shut off in the cab, well before arriving at a stiation where the cars are to be separated or added.

Now that steam heat is rarely used, and air-operated cab signal whistles are no longer used,
crew radios simplify communications regarding steam heat connections and the safe separation
of cars in the train --- protect the car inspectors when they are about to open steam heat connectors...
all that you want to have come out of the piping is, maybe, some HOT water and and a minor, residual
flow of steam vapor.

Steam heat operations, charged with live steam can be very hazardous...and inspectors can easily get burnt 
if not extremely cautious.

Stay Safe...
Remenber: " Safety is no accident"

​W.



Edited 3 time(s). Last edit at 11/11/20 17:55 by wcamp1472.

I remember even in the 1990’s we had to learn about steam heat connections and camp car rules, along with “rule 99” flagging rules when I was a new hire. None of that is taught anymore. Tempus fugit.

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I worked Passenger where the trains would terminate and the power would be cut off.  Leaving the last station, the rear man was required to signal the headend to shut off the steam and then open the gut line valve to drain off the pressure and leave the valve open.  I got into a number of private and Buz cars to access the stame valve.   

 

Thanks W on how the steam operated.