Interlocking-machines 354 287. Methods of Applying Power in Systems of Signalling 357 288. Train-staff Signalling 358 CHAPTER XXIII. 289. Evolution of the Locomotive 363 290. Increase of Locomotive Weight and Rate of Combustion of Fuel 365 291. Principal Parts of a Modern Locomotive 366 292. The Wootten Fire-box and Boiler 367 293. Locomotives with Wootten Boilers 370 294. Recent Improvements in Locomotive Design 372 295. Compound Locomotives with Tandem Cylinders 373 296. Evaporative Efficiency of Different Rates of Combustion 375 296_a_. Tractive Force of a Locomotive 376 297. Central Atlantic Type of Locomotive 378 298. Consolidation Engine, N. Y. C. & H. R. R. R. 379 299. P., B. & L. E. Consolidation Engine 380 300. L. S. & M. S. Fast Passenger Engine 381 301. Northern Pacific Tandem Compound Locomotive 382 302. Union Pacific Vauclain Compound Locomotive 384 303. Southern Pacific Mogul with Vanderbilt Boiler 384 304. The “Soo” Decapod Locomotive 385 305. The A., T. & S. F. Decapod, the Heaviest Locomotive yet Built 386 306. Comparison of Some of the Heaviest Locomotives in Use 389 PART V. _THE NICARAGUA ROUTE FOR A SHIP-CANAL._