28.  Q. How do you test for blow in high and low-pressure cylinder packing for each type of compound engine?

A. Simple the engine if a cross compound, then make test the same as for a simple engine.  For Vauclain four-cylinder compounds, test low pressure first.  A blow past the low-pressure piston will show the same as on a simple engine; a blow past the high-pressure piston will make the engine stronger on that side when working a full throttle and the exhaust from the low-pressure cylinder will be heavier.  To test the valve on either side, cover the ports.  Broken packing rings in the steam valve will show a blow in one position and be tight in another.  For tandem compound, to test high-pressure piston packing, stand engine on the top quarter, lever in back gear, drivers blocked and starting valve closed; remove back indicator plug or open back cylinder cock of high-pressure cylinder.  Steam coming from the back cylinder cock must get by the piston packing or by-pass or starting valve.  Now put reverse lever ahead and try the other indicator plug or cylinder cock.  If a leaky by-pass valve in the front end is the trouble, no steam will come through.  To test the low-pressure piston packing, place the engine in the same position, lever in position to admit steam into the front end of high-pressure cylinder.  Open starting valve, remove back indicator plug of low-pressure cylinder and give engine steam; if steam comes from the indicator plug opening or open back cylinder cock, either packing or by-pass is leaking.  To determine which one, put reverse lever in another position, close back indicator plug and open forward one; if blow still continues, the packing rings are leaking or else both by-pass valves.  Would then inspect the by-pass valves.

29.  Q. How can the blow through sleeve packing between high and low-pressure cylinder of the tandem compound be located?

A. Place the engine as before on the top quarter, put reverse lever in forward gear, see that starting valve is closed, block the drivers or set the brakes solid and open the throttle.  Until the engine moves, unless there is a leak, no steam can get into the front side of the low-pressure cylinder.  Remove the indicator plug in front end of the low-pressure cylinder for this test.

30.  Q. How test for piston packing blow with balanced compound?

A. For a Baldwin balanced compound to test the high-pressure piston packing, place the engine with the outside main pin on that side of the engine on the bottom quarter, the reverse lever in the forward notch, starting valve closed, set the brakes solid or block the drivers, remove the indicator plug in the front end of either the high or low-pressure cylinder.  With throttle open this will admit steam to the back end of high-pressure cylinder.  Steam coming out of this plug opening, will indicate a leak past the piston or the high-pressure valve.  If uncertain, next test the high-pressure