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Description
Another exercise in thought. A locomotive with a three stage combined boiler and a triple expansion 8-cylinder power plant.

The boiler stages are as follows, starting from the hottest side:
1) Firebox, water-tube, built like three-drum marine boilers. Here circulation is prioritized, and most of the heat is exchanged by radiation
2)Main boiler, water tube, built like a Babcock-Willcox, but not quite. More bent tubes instead of plates and arrays, a more modern design. The tubes are slanted forwards, so that the further forward you go the colder water you meet. So the temperature gradient is respected, and this is the priority. Most of the heat is exchanged by the gases passing in between the tubes
3)Pre-heater, fire-tube, almost like a conventional boiler, though perhaps more akin to a Franco-Crosti preheat. High pressure, lower temperature. A Wyslouch baffle is placed in the front part of the drum to further allow the cooling of exhaust gases.

This is generally a forced circulation setup with checkvalves going from >1>2>3, however the circulation can be opened if the pumping is to be stopped, by an array of tubes on both top and bottom parts of the constituent modules. The superheater is placed within (2), and from it the steam goes directly to the HP cylinders.

The HP cyl. are mounted back-to-front inside the frames, just below and to the front of (2), to minimize heat losses. The two MP cylinders are mounted slanted above the 4LP cylinders in the front and drive the axle through a rocking arm. The LP's are where mentioned, in-line in the very front and bottom.

Of course the machine can only operate on soft water.

Description
Another exercise in thought. A locomotive with a three stage combined boiler and a triple expansion 8-cylinder power plant.

The boiler stages are as follows, starting from the hottest side:
1) Firebox, water-tube, built like three-drum marine boilers. Here circulation is prioritized, and most of the heat is exchanged by radiation
2)Main boiler, water tube, built like a Babcock-Willcox, but not quite. More bent tubes instead of plates and arrays, a more modern design. The tubes are slanted forwards, so that the further forward you go the colder water you meet. So the temperature gradient is respected, and this is the priority. Most of the heat is exchanged by the gases passing in between the tubes
3)Pre-heater, fire-tube, almost like a conventional boiler, though perhaps more akin to a Franco-Crosti preheat. High pressure, lower temperature. A Wyslouch baffle is placed in the front part of the drum to further allow the cooling of exhaust gases.

This is generally a forced circulation setup with checkvalves going from >1>2>3, however the circulation can be opened if the pumping is to be stopped, by an array of tubes on both top and bottom parts of the constituent modules. The superheater is placed within (2), and from it the steam goes directly to the HP cylinders.

The HP cyl. are mounted back-to-front inside the frames, just below and to the front of (2), to minimize heat losses. The two MP cylinders are mounted slanted above the 4LP cylinders in the front and drive the axle through a rocking arm. The LP's are where mentioned, in-line in the very front and bottom.

Of course the machine can only operate on soft water.