14.  Q. How rapidly should water be supplied to the boiler?

A. No faster than it is evaporated into steam, unless just before a hard pull; or when shutting off with a heavy bright fire in the fire-box to prevent waste of steam at the pops.

15.  Q. What is the difference between priming and foaming of a locomotive boiler?

A. Priming is caused by carrying the water too high in the boiler so that when the throttle valve is opened some of it passes over with the steam in the form of a spray.  Foaming is caused by the water becoming dirty from animal or alkaline matter, so that heat makes it foam like soap suds.  Muddy water or certain vegetable matters will also make a boiler foam.

16.  Q. What should you do in a case of foaming?  What in a case of priming?

A. In a case of foaming, if possible, allow the boiler to cool off a little, increase the supply of feed water to prevent water getting too low, and whenever possible blow some of the dirty water out of the boiler, replacing it with clean water.  In case of priming, shut off the supply of feed water until the water level drops to the proper height in the boiler.

17.  Q. What danger is there when the water foams badly?  When it primes badly?

A. There is danger of knocking out cylinder heads, cutting the valves, stalling on some grade or getting on some train’s time because the engine cannot be worked to its proper power.  When shutting off steam, the water is liable to drop below the crown sheet and thus risk burning the fire-box.  When water primes badly, it is liable to break cylinder packing rings, knock out cylinder heads, break bolts in the steam chest and cut the valves.  In such a case additional oil should be fed to the steam chest until the valves are properly lubricated.

18.  Q. Suppose that with the water glass in good working order, immediately after closing the throttle the water disappeared from the water glass, what should be done?

A. Would open the throttle and endeavor to raise water until both injectors would put enough water into the boiler to make it entirely safe to close the throttle.  If unable to raise the water level to the lower gauge cock would smother the fire or put it out entirely, if necessary, keeping both injectors working.

19.  Q. What work about a locomotive should be done by the engineman?

A. Inspection of the engine both before and after the trip.  The engineer should do any necessary work on the engine after starting out on the trip to avoid breakdowns and insure getting over the road promptly.  This means tightening up any important bolts that work loose on the trip and keeping parts from working out of position, adjusting wedges and rod keys.

20.  Q. How should the work of setting up the wedges be done?

A. Place the engine on the upper quarter on the side with the loose wedge.  Do not set the brake if brake shoe will push the driving box against the defective wedge, but block engine truck wheels so the engine cannot move, push the boxes against the shoe or dead wedge with a little steam, set the wedge up until it is a snug fit, then pull it down about one-sixteenth of an inch and fasten.  Provision should be made for expansion of the box when it gets warm.