off the main line into a siding, and
draw the fire, to prevent its injuring the fire-box and tubes: when the
water has run out down to the level of the defective tube, it may be
easily plugged, and a fresh fire laid and lighted. A tube will
frequently leak to a considerable extent without absolutely requiring the
stoppage of the train; but in this case great care is necessary not to
use much steam, or urge the fire too far.

The bursting of a tube or other causes will sometimes lead to the lagging
or casing of the boiler catching fire, which should be extinguished by
throwing on water from the Tender-cistern in a fire-bucket, or from the
water crane at a Station.

2. _The failing of one of the feed pumps_.--In this case the adequate
supply of water may, with care, be maintained by one pump only. The
supply of coke must be regular, and not in large quantities; and the
steam must be economised, or the water may run low. The pump should be
repaired as soon as possible; this may frequently be done in the interval
between two trips.

3. _The breaking of a spring_.--This is an accident which does not
necessarily involve the stoppage of the train; but as working the Engine
in such a state causes an unequal strain, it should run very gently over
rough parts of the road; and if the derangement is considerable, and
cannot be repaired at the Stations, the Engine should cease running as
soon as possible.

4. _The breaking of a connecting-rod_, _or its disconnection_ by the
loss of cotters, fracture of the straps, &c. This accident, or any
disconnection which allows the piston to be driven from end to end of the
cylinder without restraint, causes expensive damage to the cylinders and
covers; and the connecting-rod, if loose, will seriously injure the
smaller gear, or may even throw the Engine off the road. The Engine
should therefore be instantly stopped, and if possible the connection
restored; if that cannot be done, the connecting-rod must be taken off,
and if on a level or a descending gradient, the train may sometimes be
drawn by a single cylinder: to do so, the slide-valve spindle of the
defective cylinder must be detached from the valve gear, by unscrewing
the nuts, and setting the slide at the middle of its stroke so as to
cover both ports.

If it should be found impracticable to move the train, the Engine might
run on alone for assistance; but in any case where the Engine is obliged
to remain stationary, the f