Ashpits (also called de-ashing Pits) (Fig. 27.4) are provided to collect the ashes falling from the locomotives. They are rectangular in shape and of a depth of about 1 m and are lined with fire bricks. The length of the ashpits should be adequate so that the longest locomotive can be de-ashed on the pit. The length is normally 15.9 m (52 ft) for BG locomotives. The ashpits are suitably sloped from the centre towards the ends so that water can be drained effectively.
The ashpits should be cleaned as often as possible. The ashes should first be dumped outside the pit and subsequently removed and stored at a suitable place for further disposal. The area around the ashpit should be paved and ample space should be provided for the picking up and storage of cinder.
Ashpits are normally provided at those points in the locomotive sheds where the locomotives turn for cleaning or dropping of fire. These are also provided in big stations at places where the locomotives collect water for de-ashing.
27.8.1 Ash Pans
Ash pans are also used for the de-ashing of locomotives. These consist of U-shaped precast reinforced concrete units placed side by side for the retention of ashes. Ash pans are normally provided in station yards. Though these pans have a very low capacity, they still have the following advantages.
(a) Easy to construct
(b) Very economical
(c) No speed restriction necessary on the main line when ash pans are provided
27.8.2 Examination Pits
Examination pits (also called outgoing pits) are used both for fire de-ashing before the locomotives leave the sheds and for outgoing engine examination and repairs. These pits should have a minimum length of 25 m with stairs at the ends to enable the staff to go underneath the locomotives for inspection and repair. The pit should be about 1 m deep and lined with fire bricks for about 6 m in the centre where fire cleaning is to be carried out. A water column should be provided by the side of each pit.
27.8.3 Drop Pits
Drop pits are provided in order to enable the wheels of the locomotives to be removed for examination, repairs, and renewals. These pits are normally provided at right angles to the track. Mobile jacks are installed to enable the wheels and axles to be removed.