And while we're talking about highly specialized firefighting apparatus... while I don't think Chicago FD ever ran anything quite like the FDNY Mack Super Pumper, they are well known for their use of a piece of apparatus known as a "turret wagon". Basically, it's a big-ass truck with a huge deluge gun (aka "monitor" or "turret") mounted on the back, and with a big intake manifold for receiving multiple supply lines. You could think of a "turret wagon" as being conceptually akin to the "Satellite" units that were part of the FDNY Super Pumper System.
Anyway, one of the best known Chicago Turret Wagons was "Big John" (aka 6-7-3).
Not sure if CFD still maintain any Turret Wagons in contemporary times or not, but variations on the concept are still found, particularly in industrial fire departments that protect high hazard sites like oil refineries, certain chemical plants, etc.
It's interesting to think about - because Big John obviously takes some time to connect/setup but then can (apparently) deliver 10,000 gallons per minute as long as there's water in the pipes.
Whereas a modern tanker truck can do 1,000 GPM for 2 or 3 minutes, but can do it immediately upon arriving onsite.
It's also relative to how fire-fighting has changed over time, modern buildings that are big enough to NEED the Big John are also much more fire-resistant (concrete instead of wood, etc).
SysAdmin related: I was once talking to a fire chief and I asked about how much water the fire engines carried. He said that they carry about enough to put out the typical house fire. The first engine on scene immediately jumps to fighting the fire. The second engine on scene hooks the first engine up to the water supply before going on to fight the fire.
I've often thought about that when there's a work crisis: If I'm the second on the scene, what can I do to support those fighting the fire right now, before jumping in.
Our engine holds 1200 gallons. It goes in first* and starts putting the wet stuff on the red stuff.
As the engine drives in it drops a 3" hose along its path. Next is our big tender with 3000 gallons. It stops at the street and connects to the dropped hose to pump more water up to the engine.
The tender also has a drop tank -- think about a portable kids' wading pool but much larger and deeper. Shuttle tenders refill the drop tank while our big tender draws from it to continue supplying the engine.
We don't have fire hydrants, so this is the dance we have to do.
* It's very important to park the engine close to the fire but not too close. Ask me how I learned this.
> It's very important to park the engine close to the fire but not too close. Ask me how I learned this.
I was a farm hand as a summer job to cover beer and books in my college years. We harvested wheat which carries a high fire risk. Most farms kept a tractor with a large plow hooked up so it could quickly encircle and contain any fires.
Pulling a 40’ wide plow is hard. Tractors can do it because they have huge engines that suck in huge amounts of oxygen.
Just like fires.
If you get a tractor too close to a fire it starves for oxygen and stalls out. The plow becomes an anchor. There’s just enough time to bail out before the tires catch fire. After a few minutes the whole thing is a pile of ash and melted steel.
Wow. We're probably more rural and can't fit such large apparatus in many places we have to go. Out our type 1 engine carries 1,000 gallons, and our type 3 (wildland) 500 gallons and our tenders have 2,000.
1,000 isn't going to put out a house fire unless it's really small and not fully involved. The past two good structure fires we had took 20,000 and 60,000 to gallons respectively.
>I've often thought about that when there's a work crisis: If I'm the second on the scene, what can I do to support those fighting the fire right now, before jumping in.
Great! Now I'll have to see this quote over an image of a sweaty firefighter on LinkedIn every 3 weeks for eternity.
> I've often thought about that when there's a work crisis: If I'm the second on the scene, what can I do to support those fighting the fire right now, before jumping in.
A lot of it depends on the size and skill-set of your team and the escalation routes available to you, but in general (and off the top of my head):
- Get the first people on scene to give a summary of the problem as they know it. Make sure everyone actually agrees on what the problem is and what symptoms have been observed. Understand what areas people are currently investigating and make sure they aren't trampling over each other or actually making the situation worse [1]
- Make sure the situation hasn't evolved whilst the first on scene have been investigating the initial symptoms. It's easy to get lost in the weeds digging into a handful of monitoring alerts only to look up and realise there's now 300 and the original problem is only a small part of what's going on.
- If there isn't one already and you're not better doing something else, become incident commander. When done right it's an extremely important and useful role.
- Take over external communication and protect the team from distractions
- Start assessing escalation options
- Take copious notes and keep a timeline
- Act as a shared memory and keep people honest
- Have a less panicked, wider (non minutia) view of the problem
- Start collating and pulling up documentation/schematics so the people at the coalface can quickly query it rather than getting distracted searching for it.
- Be ready to jump, for when someone inevitably asks "can someone check..." or "does anyone know"
- Keep track of the "shared truth" of the incident as it evolves. What have we witnessed, what do we believe is the cause, _why_ do we believe that? Have we invalidated anything, do we need to reassess, are we sure logical lynchpins aren't confirmation bias or dyslexia?
- Onboard new people and hand over if appropriate.
Being at the coalface when it's on fire is a very different view of the world to watching other people panic and singe their fingers. It's also very easy to get lost in a chain of technical problems [2] when it's mostly irrelevant to the wider picture.
If you get a moment, it can also be a good time to assess how useful your monitoring is during an actual event.
[1] "Hey, server x has flagged on monitoring and my ssh session is hung waiting for a login prompt!" I've been round the houses enough to know this is probably OOM and if I just wait, I'm likely to finally get in. I also know that saying this in a room of 20 technical people, means the server is now processing 22 new ssh sessions and now no one is getting anywhere.
[2] The famous Malcolm in the Middle intro where Hal is tasked with changing a lightbulb and ends up repairing the car. Except in my example the bulb is actually fine and there's a power cut we missed. https://www.youtube.com/watch?v=AbSehcT19u0
My dad worked on the Space Shuttle main engine program in the 80s. One of the things they built was the turbopump [0], which generated 23,000HP (and could drain your average home swimming pool in one minute).
Seeing the test firings of the pump was pretty amazing, draining one "swimming pool" and filling another in a minute.
The numbers on rocket engines are just ridiculous. The turbine on the F1 engines on the Saturn V's first stage generate about 40MW just to pump the fuel and oxygen. 5 of them on the rocket is 200MW which is a respectablly sized power plant, or about 1/2 of a Nimitz aircraft carrier (which is able to push a floating city through the water at nearly 40mph).
The comparisons which stick in my head are that the Saturn V's first-stage fuel pumps were roughly equal in power to a naval destroyer's engines, and the five F1 engines delivered as much energy as France's entire electrical grid (presumably contemporaneously). This from books read as I was a wee lad.
That's always blown my mind about rocket engines. If the FUEL PUMP has that much power, the overall machine energy flow must be insane. Especially in such a small package.
Powered the absolute monster that was the Tempest (up to the Mk 2 - they did have reliability issues they never quite solved but 3000+HP out of an engine that weighs barely more than a tonne dry will do that)
Was happy to see the name re-used for our upcoming fighter.
We also called the Eurofighter the Typhoon and the (WW2) Typhoon (also a Sabre engine) was the predecessor of the Tempest - it started as a re-wing of the Typhoon but enough changes where made to give it a new name.
The type 55 "deltic" locomotives, named after army regiments used to do the east coast Edinburgh-London train run, there were 22 of them in service and one in the science museum London. They had the first 100mph rating for diesel passenger service.
The engine had a unique characteristic whine or whistle. As an avid train spotter at Waverley station in edinburgh I loved hearing it, saw every one and was in the cab of two thanks to long suffering kind engine drivers.
There was a mini deltic too. I'm not sure it went beyond a testbed loco.
Those are amazing engines. It's a pity that in the future we'll just be using magnets and coils, there something about these designs that moves me in a way that nothing electrical ever will. And I'm a great fan of renewable energy, and realize that the pollution that has been created (and is still being created) is absolutely unsustainable.
About 12 years ago they used to use 55022 as a shunter at Springburn yard, because it was "road legal" and could couple up to older carriages that were being taken in for refurbishment. Nice cushy retirement job, easy shifts and a well-appointed engine shed to park up it at night ;-)
I used to hear it all the time, working in a nearby industrial site. I'd maybe just take five minutes to sit outside and drink my coffee, listening to that weird shimmering howl.
There are no good recordings of it on Youtube and I suspect like a lot of things you have to experience it for yourself.
> avid train spotter at Waverley station in edinburgh
We probably met. I was there every day traveling to and from school but did casual trainspotting on the side. Oblivious someone would one day write a book with that title..
Piston engines got pretty wild before turbines eventually took over the world. The most efficient ones were more efficient than today's turbines in terms of BSFC[0]. One of the most interesting to me was the Napier Nomad[1], which used turbo- and super-charging. However, the turbo had secondary fuel injection and effectively ran as a turbine to drive the compressor.
Gas turbines aren't generally noted for their efficiency, but rather:
- Power-to-weight ratios. Critical in aerospace applications.
- Long duty cycles. Everything spins, reducing wear-and-tear relative to reciprocating designs. Maintenance on piston engined aircraft during WWII was a major logistical concern.
- Raw speed. Supersonic flight requires high rotary speeds, and the few propeller-driven aircraft which achieved this had ... issues. Ground crews and pilots suffered health effects from the noise alone, and notoriously often flat refused to work with the XF-84H "Thunderscreech": <https://en.wikipedia.org/wiki/Republic_XF-84H_Thunderscreech...>. At near-supersonic speeds and above, propeller blade tips themselves break the sound barrier, losing aerodynamic flow over the blades, making quite a racket, and greatly reducing efficiency.
Propeller-driven planes remain more efficient than jets in many instances, though last I checked US military forces rely on turboprops over reciprocating engines in virtually all instances, possibly excepting some civilian-based (e.g., Cessna / Piper, etc.) trainer or observer variants.
Those exhaust driven turbines didn't just drive the compressor like is typical with turbochargers, but was also mechanically linked to the crank shaft so the turbine contributed to the overall power output of the engine directly, not just by forcing more air into the cylinders. That's what made them "turbo-compound."
The youtube channel "Greg's Airplanes and Automobiles" has a nice video about turbo compound engines.
They're unique. Originally designed to power fast torpedo boats during WW2, three of these powerful and compact engines would churn out plenty of power for the boat up to 50 kt.
There are numerous "atypical" piston engine layouts, though I cannot recall precisely where I'd seen a reference, probably on YouTube ~10 years ago.
The basics are a single piston, dual (often opposed at an angle or flat-head design as on older BMW motorcycles), in-line (usually 4-cylinder), or V (as in V-6, V-8, V-12, etc.)
Then there are radial engines used in piston-driven aircraft. These virtually always have an odd cylinder count, to prevent locking (there's always an unbalanced force in the direction of intended rotation, or so one hopes).
There are various rotary engines, with the Wankel design best known. Very high power-to-weight ratios as a result of having three combustion chambers per rotor, but a relative short lifecycle due to wear, and some compromises in efficiency. "Flying car" company Moller International, out of Davis, CA (and apparently inactive since 2015) had at its core a Wankel-based powerplant, with four pairs of counter-rotating engines powering four ducted fans. It sounds like all the angry hornets in operation.
Scavenging here means getting the exhaust from the previous cycle out of the cylinder and replacing it with fresh air. Technically all internal combustion engines do it one way or another, but usually you hear the word in relation to two stroke engines. Two strokes don't have discrete "suck" and "blow" steps so those need to be done at the same time. With two stroke diesels, that was done using blowers to basically force out the exhaust by blowing in fresh air.
Generally speaking at least, two stroke diesel engines weren't super efficient, but did offer great power output relative to their size.
It amazes me what we manage to figure out on the mechanical side of things. Just look at motorcycle engines. Screaming along at upwards of 20k RPM and just taking it in stride and moving people down the road at what might as well be supersonic speed.
This thing feels like a mortal danger to the (up to 8x!) iron pipes / hydrants it's pulling from, that it'd want to just chew up the very pipes themselves! Or to the building it's hurling 37 tons of water a minute at! I don't understand how a connector hose wouldn't collapse, how it maintains any cross-section rather than being sucked into collapse.
Also wondering: what replaced this!
(Ed: great reply from Mindcrime. Also, the new Ferrara Super Pumper shows a very impressive ribbed(?) 8-inch "hard suction" hose! There's a whole wikipedia section for these drafting/vacuum hoses: https://en.wikipedia.org/wiki/Suction_hose)
A collection of smaller pumps and monitors, which is likely a better scheme, in terms of flexibility and fault tolerance. While a remarkable design, the single pump with long hoses to multiple hydrants, then radiating to multiple monitors, is a system that takes great coordination and precious time to deploy and rework in action.
The Napier Deltic engine is the party piece in all this. It is an ambitious and yet successful design, intended to push the limit of power-to-weight in a diesel engine. I investigated the state of current diesel locomotive engines in comparison to the Deltic and it remains, to this day, the highest power-to-weight diesel engine in use for locomotives. (There are half a dozen still running in the UK today in limited service.) I've personally visited the Bay City museum to see this engine.
These engines require forced induction; they cannot run naturally aspirated. In its various naval, rail and other applications there were many different induction designs applied to the Deltic: turbos, superchargers and combinations of both. Today, we have electric forced induction, enabled by the high performance electric motors that have emerged elsewhere in transport applications. One thinks of what diesel wonders might be created by combining the Deltic design with electric forced induction.
I believe most contemporary marine two stroke diesels use electrical blowers for scavenging at low speeds. At higher speed the turbocharger spins up and takes over, and the electric blowers are shut down.
This thing feels like a mortal danger to the (up to 8x!) iron pipes / hydrants it's pulling from,
When pumping a fire engine supplied by a hydrant (or any other pressurized source, as opposed to drafting from a static water source like a pond or lake) there's an idea of "residual pressure" which is monitored by a gauge on the pump panel. The engineer is responsible for making sure the residual pressure doesn't drop below the level where damage would occur to the water system, supply hose, or the pump itself. It's been a few years, but I think most departments spec somewhere around 20psi as the minimum residual pressure they allow.
Also wondering: what replaced this!
The Super Pumper[1], of course! :-)
The new one isn't quite as extreme, not tractor drawn and no separate engine. This is more of a traditional fire engine style platform, but the specs are still pretty impressive.
You don't bust this out until the building is already at risk anyway, so the amount of water is considered "the better option".
(Which is why almost ANY fire is a total structure loss unless you can contain it nearly instantly, because the water used to fight it destroys nearly everything. Only if the building is large, concrete, or the damage limited is it worth repairing; most fire-damaged houses get pulled down as it's cheaper overall.)
I imagine the hydrants were operated at positive pressure. Water mains are generally somewhere between 40 and maybe 120 psi gauge. You don’t gain a whole lot by sucking on them - at most you get to -14 psi, and you do not want to boil the water (aka cause cavitation) in your pump.
Ah, the Mack Super pumper. Shame Mack started to struggle in the 60s until the 80s and got out of the fire truck business. They had some very interesting designs in terms of cab design and components. I always loved the F model cab-over which were produced until the early 80s which is what the CF fire truck was built on.
The article says the "super pumper" could supply 8,800 gallons per minute, and it came with three "satellite trucks [...] not burdened with a pump of their own"
Your basic modern fire pump unit can pump 2,200 gallons per minute (if you can find a water source that'll give you that much) and it'd typically have a crew of 4-5 firefighters on board.
So you'd probably replace it with 4 regular fire trucks? Then you've got just as much pump capacity, plus you've got the flexibility to send the trucks to different places.
(if you can find a water source that'll give you that much)
Note that, for what it's worth, fire pumps are generally rated for their capacity when drafting from a static water supply (think, pond, lake, river, etc). Basically all modern fire pumps can easily exceed their rated capacity by a pretty good margin when pumping from a pressurized source, but then you're back to your point of "do you have a source that can supply that?" Still, there are ways. In my firefighting days we had some hydrants in our district (the ones on the big 30" main that ran right down the middle of the county in particular) that could individually supply 2000gpm. And nothing says you are restricted to using one hydrant! There are also all sorts of complex water supply evolutions one can run, involving relay pumping with multiple engines, drafting and using hydrants, etc.
Readit News
Anyway, one of the best known Chicago Turret Wagons was "Big John" (aka 6-7-3).
https://chicagoareafire.com/blog/2013/04/chicago-fd-turret-w...
https://chicagoareafire.com/blog/2013/04/chicago-fd-turret-w...
Not sure if CFD still maintain any Turret Wagons in contemporary times or not, but variations on the concept are still found, particularly in industrial fire departments that protect high hazard sites like oil refineries, certain chemical plants, etc.
Whereas a modern tanker truck can do 1,000 GPM for 2 or 3 minutes, but can do it immediately upon arriving onsite.
https://www.piercemfg.com/fire-trucks/tankers/bx-tanker
It's also relative to how fire-fighting has changed over time, modern buildings that are big enough to NEED the Big John are also much more fire-resistant (concrete instead of wood, etc).
I've often thought about that when there's a work crisis: If I'm the second on the scene, what can I do to support those fighting the fire right now, before jumping in.
As the engine drives in it drops a 3" hose along its path. Next is our big tender with 3000 gallons. It stops at the street and connects to the dropped hose to pump more water up to the engine.
The tender also has a drop tank -- think about a portable kids' wading pool but much larger and deeper. Shuttle tenders refill the drop tank while our big tender draws from it to continue supplying the engine.
We don't have fire hydrants, so this is the dance we have to do.
* It's very important to park the engine close to the fire but not too close. Ask me how I learned this.
I was a farm hand as a summer job to cover beer and books in my college years. We harvested wheat which carries a high fire risk. Most farms kept a tractor with a large plow hooked up so it could quickly encircle and contain any fires.
Pulling a 40’ wide plow is hard. Tractors can do it because they have huge engines that suck in huge amounts of oxygen.
Just like fires.
If you get a tractor too close to a fire it starves for oxygen and stalls out. The plow becomes an anchor. There’s just enough time to bail out before the tires catch fire. After a few minutes the whole thing is a pile of ash and melted steel.
1,000 isn't going to put out a house fire unless it's really small and not fully involved. The past two good structure fires we had took 20,000 and 60,000 to gallons respectively.
Rural properties I'm familiar with required a 3,000 gallon water tank with fire-connection far enough from the main structure as to be accessible.
But ask the fire department how they'd approach your house, and put the hydrant on that road; it might NOT be the road/driveway you normally come up!
Great! Now I'll have to see this quote over an image of a sweaty firefighter on LinkedIn every 3 weeks for eternity.
I feel gross.
A lot of it depends on the size and skill-set of your team and the escalation routes available to you, but in general (and off the top of my head):
- Get the first people on scene to give a summary of the problem as they know it. Make sure everyone actually agrees on what the problem is and what symptoms have been observed. Understand what areas people are currently investigating and make sure they aren't trampling over each other or actually making the situation worse [1]
- Make sure the situation hasn't evolved whilst the first on scene have been investigating the initial symptoms. It's easy to get lost in the weeds digging into a handful of monitoring alerts only to look up and realise there's now 300 and the original problem is only a small part of what's going on.
- If there isn't one already and you're not better doing something else, become incident commander. When done right it's an extremely important and useful role.
Being at the coalface when it's on fire is a very different view of the world to watching other people panic and singe their fingers. It's also very easy to get lost in a chain of technical problems [2] when it's mostly irrelevant to the wider picture.If you get a moment, it can also be a good time to assess how useful your monitoring is during an actual event.
[1] "Hey, server x has flagged on monitoring and my ssh session is hung waiting for a login prompt!" I've been round the houses enough to know this is probably OOM and if I just wait, I'm likely to finally get in. I also know that saying this in a room of 20 technical people, means the server is now processing 22 new ssh sessions and now no one is getting anywhere.
[2] The famous Malcolm in the Middle intro where Hal is tasked with changing a lightbulb and ends up repairing the car. Except in my example the bulb is actually fine and there's a power cut we missed. https://www.youtube.com/watch?v=AbSehcT19u0
Seeing the test firings of the pump was pretty amazing, draining one "swimming pool" and filling another in a minute.
[0] https://en.wikipedia.org/wiki/RS-25#Turbopumps
Though that's just gravity-fed, of course. Still pretty cool though, I think (:
[1] https://en.wikipedia.org/wiki/Sound_suppression_system
> https://en.wikipedia.org/wiki/Napier_Deltic
https://en.wikipedia.org/wiki/Napier_Sabre (1938).
Powered the absolute monster that was the Tempest (up to the Mk 2 - they did have reliability issues they never quite solved but 3000+HP out of an engine that weighs barely more than a tonne dry will do that)
https://en.wikipedia.org/wiki/Hawker_Tempest
Was happy to see the name re-used for our upcoming fighter.
We also called the Eurofighter the Typhoon and the (WW2) Typhoon (also a Sabre engine) was the predecessor of the Tempest - it started as a re-wing of the Typhoon but enough changes where made to give it a new name.
Just a devastating superprop in its day.
The engine had a unique characteristic whine or whistle. As an avid train spotter at Waverley station in edinburgh I loved hearing it, saw every one and was in the cab of two thanks to long suffering kind engine drivers.
There was a mini deltic too. I'm not sure it went beyond a testbed loco.
I used to hear it all the time, working in a nearby industrial site. I'd maybe just take five minutes to sit outside and drink my coffee, listening to that weird shimmering howl.
There are no good recordings of it on Youtube and I suspect like a lot of things you have to experience it for yourself.
We probably met. I was there every day traveling to and from school but did casual trainspotting on the side. Oblivious someone would one day write a book with that title..
[0]https://en.wikipedia.org/wiki/Brake-specific_fuel_consumptio... [1]https://en.wikipedia.org/wiki/Napier_Nomad
- Power-to-weight ratios. Critical in aerospace applications.
- Long duty cycles. Everything spins, reducing wear-and-tear relative to reciprocating designs. Maintenance on piston engined aircraft during WWII was a major logistical concern.
- Raw speed. Supersonic flight requires high rotary speeds, and the few propeller-driven aircraft which achieved this had ... issues. Ground crews and pilots suffered health effects from the noise alone, and notoriously often flat refused to work with the XF-84H "Thunderscreech": <https://en.wikipedia.org/wiki/Republic_XF-84H_Thunderscreech...>. At near-supersonic speeds and above, propeller blade tips themselves break the sound barrier, losing aerodynamic flow over the blades, making quite a racket, and greatly reducing efficiency.
Propeller-driven planes remain more efficient than jets in many instances, though last I checked US military forces rely on turboprops over reciprocating engines in virtually all instances, possibly excepting some civilian-based (e.g., Cessna / Piper, etc.) trainer or observer variants.
The youtube channel "Greg's Airplanes and Automobiles" has a nice video about turbo compound engines.
https://everythingaboutboats.org/napier-deltic/
The basics are a single piston, dual (often opposed at an angle or flat-head design as on older BMW motorcycles), in-line (usually 4-cylinder), or V (as in V-6, V-8, V-12, etc.)
Then there are radial engines used in piston-driven aircraft. These virtually always have an odd cylinder count, to prevent locking (there's always an unbalanced force in the direction of intended rotation, or so one hopes).
<https://en.wikipedia.org/wiki/Radial_engine>
There are various rotary engines, with the Wankel design best known. Very high power-to-weight ratios as a result of having three combustion chambers per rotor, but a relative short lifecycle due to wear, and some compromises in efficiency. "Flying car" company Moller International, out of Davis, CA (and apparently inactive since 2015) had at its core a Wankel-based powerplant, with four pairs of counter-rotating engines powering four ducted fans. It sounds like all the angry hornets in operation.
<https://en.wikipedia.org/wiki/Moller_M400_Skycar>
Wikipedia lists some other unusual designs as well: <https://en.wikipedia.org/wiki/Reciprocating_engine#Miscellan...>.
I believe that the axial engine may have been featured in that video mentioned in 'graph 1:
<https://en.wikipedia.org/wiki/Axial_engine>
Any tech that includes the word “scavenged” must be cool and efficient
Generally speaking at least, two stroke diesel engines weren't super efficient, but did offer great power output relative to their size.
Also wondering: what replaced this!
(Ed: great reply from Mindcrime. Also, the new Ferrara Super Pumper shows a very impressive ribbed(?) 8-inch "hard suction" hose! There's a whole wikipedia section for these drafting/vacuum hoses: https://en.wikipedia.org/wiki/Suction_hose)
A collection of smaller pumps and monitors, which is likely a better scheme, in terms of flexibility and fault tolerance. While a remarkable design, the single pump with long hoses to multiple hydrants, then radiating to multiple monitors, is a system that takes great coordination and precious time to deploy and rework in action.
The Napier Deltic engine is the party piece in all this. It is an ambitious and yet successful design, intended to push the limit of power-to-weight in a diesel engine. I investigated the state of current diesel locomotive engines in comparison to the Deltic and it remains, to this day, the highest power-to-weight diesel engine in use for locomotives. (There are half a dozen still running in the UK today in limited service.) I've personally visited the Bay City museum to see this engine.
These engines require forced induction; they cannot run naturally aspirated. In its various naval, rail and other applications there were many different induction designs applied to the Deltic: turbos, superchargers and combinations of both. Today, we have electric forced induction, enabled by the high performance electric motors that have emerged elsewhere in transport applications. One thinks of what diesel wonders might be created by combining the Deltic design with electric forced induction.
When pumping a fire engine supplied by a hydrant (or any other pressurized source, as opposed to drafting from a static water source like a pond or lake) there's an idea of "residual pressure" which is monitored by a gauge on the pump panel. The engineer is responsible for making sure the residual pressure doesn't drop below the level where damage would occur to the water system, supply hose, or the pump itself. It's been a few years, but I think most departments spec somewhere around 20psi as the minimum residual pressure they allow.
Also wondering: what replaced this!
The Super Pumper[1], of course! :-)
The new one isn't quite as extreme, not tractor drawn and no separate engine. This is more of a traditional fire engine style platform, but the specs are still pretty impressive.
[1]: https://www.firefighternation.com/lifestyle/new-fdny-super-p...
(Which is why almost ANY fire is a total structure loss unless you can contain it nearly instantly, because the water used to fight it destroys nearly everything. Only if the building is large, concrete, or the damage limited is it worth repairing; most fire-damaged houses get pulled down as it's cheaper overall.)
Mack was awarded the contract to build the truck in 1964 and by the end of the year, the unit was nearly ready to hit the streets of NYC.
Seems amazingly fast by current standards. Those were the days!
See:
https://www.firefighternation.com/lifestyle/new-fdny-super-p...
Your basic modern fire pump unit can pump 2,200 gallons per minute (if you can find a water source that'll give you that much) and it'd typically have a crew of 4-5 firefighters on board.
So you'd probably replace it with 4 regular fire trucks? Then you've got just as much pump capacity, plus you've got the flexibility to send the trucks to different places.
Note that, for what it's worth, fire pumps are generally rated for their capacity when drafting from a static water supply (think, pond, lake, river, etc). Basically all modern fire pumps can easily exceed their rated capacity by a pretty good margin when pumping from a pressurized source, but then you're back to your point of "do you have a source that can supply that?" Still, there are ways. In my firefighting days we had some hydrants in our district (the ones on the big 30" main that ran right down the middle of the county in particular) that could individually supply 2000gpm. And nothing says you are restricted to using one hydrant! There are also all sorts of complex water supply evolutions one can run, involving relay pumping with multiple engines, drafting and using hydrants, etc.