As far as I know condensing steam locomotives were never built for or used by American railroads and I've often wondered why. From what I've read the South African Ry's condensing 4-8-4's were a success and achieved a 90% reduction in water and a 10% reduction in coal usage as compared to their non-condensing counterparts. IMHO these savings should have made condensers the accepted norm on railroads all over the US and particularly so in the southwest where water availability and quality was a constant problem. It also seems logical to think these savings would, in fairly short order, recoup the higher initial cost of a condensing locomotive.
The SAR's condensers used a steam turbine driven fan to supply combustion air (draft). I believe it would have been better to install a slightly higher output turbo-generator to power an electrically driven fan with infinitely variable cfm throughout its capacity range. Just think what an advantage this would be over an exhaust steam induced draft that was uncontrolled and varied widely depending on how hard the engine was working. While hard to quantify in $, the vast reduction in smoke, soot and cinder stack emission would be a real plus particularly in cities where this was a constant source of friction between residents and local governments and the railroads.
I believe maintenance costs would have been higher simply due to the intricacies of the condenser mechanism but there would be some at least partial offsets such as blastpipe elimination and reduced boiler tube frictional wear and tear. Other savings would accrue in the costs of boiler water treatment and the installation, maintenance and operation of numerous water storage and pumping facilities and water troughs. The reduction in water stops would enable faster schedules and improved operating efficiencies.
I believe the technology to design build and operate a condensing locomotive was available by 1920 if not earlier but AFAIK none of the locomotive builders or railroads seriously considered it. The only reference to an American condensing locomotive I've been able to find is in the design criteria for the ACE 3000 Project. I'd be interested in hearing others thoughts on this subject.
Mark
I think the 1938 GE turbines (steam turbine electric) had condensers. The main problem they had, shared with the C&O passenger turbines and N&W's Jawn Henry, was that fly ash got into all of the electrical machinery. That might explain SAR's choice of a steam turbine driven blower, which probably also simplified maintenance. Were the SAR engines' condensing fans electric or turbine?
The London Underground tried condensing by the simple expedient of running exhaust steam into the water tank, thereby getting a feedwater heater on the side. Electricity put an end to that project.
rcdrye I think the 1938 GE turbines (steam turbine electric) had condensers. The main problem they had, shared with the C&O passenger turbines and N&W's Jawn Henry, was that fly ash got into all of the electrical machinery. That might explain SAR's choice of a steam turbine driven blower, which probably also simplified maintenance. Were the SAR engines' condensing fans electric or turbine? The London Underground tried condensing by the simple expedient of running exhaust steam into the water tank, thereby getting a feedwater heater on the side. Electricity put an end to that project.
It seems to me that fly ash was largely a problem created by the intermittent blasts of exhaust steam particularly when an engine was working hard at low speeds. Eliminate exhaust steam as a means of supplying draft air and the problem of fly ash is greatly reduced if not eliminated entirely. It certainly would not be a problem on an oil burner. I never heard of fly ash adversely affecting the performance of a locomotive turbo-generator. The steam turbine electrics were loaded with a massive amount of electrical gear, generators, motors and switchgear, which made them vulnerable to electrical malfunctions caused by the environment in which they operated. A simple motor driven blower could be easily located and shielded from any fly ash or road dust. I actually think it would be a far less complex and more easily maintained arrangement than a turbine driven blower.
I don't know for sure but believe the SAR's condensing fans were exhaust steam turbine driven. The condensing tenders were extremely long. I'd guess them to be on the order of twice the length of a conventional tender. I wouldn't be surprised if this didn't require the extension of some turntables and roundhouse stalls. Of course this wouldn't be necessary if they ran in territories where the super long Garratts were also operated.
The subject of SAR's condensing locos came up in a Trains Magazine thread. It was pointed out that SAR had identical locos without condensers running in the less arid part of the country, indicating condensers were only desirable where water was scarce.
http://cs.trains.com/trn/f/740/t/209944.aspx?sort=ASC&pi332=2
Rob, I learned about fly ash as a kid growing up less than 1/2 block from the IC's six track main south of Chicago. We lived about a mile south of where the Markham Yard lead tracks joined the mainline and there was a constant parade of trains. Southbound freights headed by the IC's big Mountain type road engines would pass by working hard to get their trains rolling on an about 1/2% upgrade and fly ash fell like rain on our house and yard. Mother liked to wash clothes on Monday but if the prevailing wind was from across the tracks she'd postpone her washing to another day.. Southern Illinois bituminous coal produced a particularly sooty form of fly ash which would mottle any clothes hung on the line to dry.
The Nov. issue of Trains in the Q&A section had an item on condensing locos. Apparently the SARs were not a success in that situation. There was a lot of extra maintenance, and they were converted back to standard engines.
The 90 Class 25C (condensing) engines of the SAR contained a number of new and largely untested innovations. All the trechnical articles I've read agree that these engines turned in impressive performance metrics after their initial design bugs had been worked out or around. Most notable was their 85-90% reduction in water usage (leading to 500 mile intervals between water stops) and 10-15% reduction in coal consumption.
The steam turbine driven draft and tender mounted condenser fans were largely responsible for the 25C's higher maintnacnce cost as compared to the Class 25NC (non-condensing) engines. The draft fan and its turbine drive were located in the smokebox which is far from an ideal operating environment. IMHO it would have been far better to mount this on the exerior of the smokebox or on the pilot beam and possibly drive the fan by an electrical motor instead of the turbine. The tender mounted condenser fans were powered by a steam turbine connected by a flexible drive shaft to a gearbox on each fan - small wonder that was costly to maintain. Again IMHO it would have been far better to drive each condenser fan by it's own direct mounted electric motor.
One thing to keep in mind is that these engines were narrow gauge by US standards. 3'-6" (Cape Gauge) is the prevailing standard gauge on the SAR. This probably somewhat limited options available to the engine's designers and it's logical to assume that a greater range of design options would have been possible had the engines been 4' 8-1/2" gauge.
It's true that the 25C's were eventually converted to 25NC's but this was not because as condensers they were unsuccessful. Rather as diesels began to replace them in the Great Karoo territiory (and other water problem areas) they were reassigned all over the SAR system where the skills, parts and facilities to meet their unique maintenance requirements were not available. This coupled with the fact they were to be operated where water conservation wasn't a major factor led to the decision to convert them to non-condensers.
Keep in mind that these engines were built in the 1950's near the end of the steam era. Had they come along earlier (say 1925) there would have been a lot more emphasis on design improvements and innovations. IMHO this would have led to the widespread (including here in the US) adoption of condensing locomotives as the way to go.
The SAR condensing locos may have been a mechanical success, but were a commercial failure, as evidenced by their short lives. Yes it would have been interesting to have seen more condensing loco experiments, nevertheless, steamships had condensing technology almost from the start, and after a 100 years of development still suffered the same fate as steam rail.
rcdrye I think the 1938 GE turbines (steam turbine electric) had condensers. The main problem they had, shared with the C&O passenger turbines and N&W's Jawn Henry, was that fly ash got into all of the electrical machinery.
I think the 1938 GE turbines (steam turbine electric) had condensers. The main problem they had, shared with the C&O passenger turbines and N&W's Jawn Henry, was that fly ash got into all of the electrical machinery.
The 1938-39 GE "Turbomotives" burned oil, not coal and had very little fly ash. The main problem was dealing with the high pressure steam cycle and getting adequate performance out of the condensers, particularly with the 100+ degree heat on the LA&SL line.
- Erik
MidlandMike The SAR condensing locos may have been a mechanical success, but were a commercial failure, as evidenced by their short lives. Yes it would have been interesting to have seen more condensing loco experiments, nevertheless, steamships had condensing technology almost from the start, and after a 100 years of development still suffered the same fate as steam rail.
Steam ships suffering the same fate as steam rail? Well, yes and no, it depends on the application. Cruise ships use diesel engines as they're required to do "stop and start" sailing, one port-of-call to another, usually within a 24 to 48 hour period. Diesel engines work best at this. Ships that are under way for extended periods and won't stop for weeks, say supertankers or cargo ships, still use steam, it's more efficient than diesel for long runs. And of course the Navy's nuclear powered ships are steam powered, the reactor is just a big heat source to boil water.
Firelock76 Steam ships suffering the same fate as steam rail? Well, yes and no, it depends on the application. Cruise ships use diesel engines as they're required to do "stop and start" sailing, one port-of-call to another, usually within a 24 to 48 hour period. Diesel engines work best at this. Ships that are under way for extended periods and won't stop for weeks, say supertankers or cargo ships, still use steam, it's more efficient than diesel for long runs. And of course the Navy's nuclear powered ships are steam powered, the reactor is just a big heat source to boil water.
I made an assumption based on Great Lakes boats, where there are only a few steamers left, and they were mothballed during this recession. While their trips are short, they don't seem to shut down even in the short time in port. I've seen ore ships constantly re-position them selves during loading, and I'm sure they need power for the self-unloader.
I've read up a little more on the subject of ocean-going ships and I find that many cargo ships are diesel for fuel efficiency, and many of the steam ships still left use their cargo for fuel, such as coal or LNG. I also heard they are having a harder time finding marine engineers qualified in steam. Sounds all to familiar.
I think Mike is referring to the fact that reciprocating steam engine driven ships went the way of steam locomotives. Modern steamships of course use turbines which exhaust steam into a heat exchanger that uses seawater to condense the steam into reuseable boiler feedwater.
KCSfan I think Mike is referring to the fact that reciprocating steam engine driven ships went the way of steam locomotives. Modern steamships of course use turbines which exhaust steam into a heat exchanger that uses seawater to condense the steam into reuseable boiler feedwater. Mark
I was referring to steam turbines. My research has been very general and limited. Maybe you could recommend a good website as to what they are building now.
Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!
Get the Classic Trains twice-monthly newsletter