When a car overhaul is done , its really a restoration a 100% restoration of old item to make it brand new
Car overhaul includes
a) Bringing the car unit into Mechanical Complex
b) The mechanics, then carefully detach the external components (doors , wind shield, hoods)
c) After the external items are removed the engine is removed from the car sperated (when engine over haul is being done)
d) The body is completely deassembled , seats are removed, the floor is removed
e) Car's tires are removed , and then the springs and shocks are replaced brake systems are upgraded
f) The dash board elements are easy to replace , or upgrade once the car in this state
with brand new elements like digital monitors, or systems
g) Wiring is corrected in the car
h) Any rusted elements are replaced or weilded toegther for a brand finish
i) The engine is opened up seperately
k) Every part of the engine is opened to core, and the engine goes thru a degreaser
l) The components , valuves are replaced and any damaged pistons are removed and replaced
m) The degreaser removed all the sludge from the engine's internals
o) The engine is assembled back into one working component its tested out to working condition again proir to addition in car
p) The engine external is painted brandnew color
q) The part is reintroduced into the car, with new hoses , and brandnew shinning parts
l) The other superficial parts , the car's floor is redone , seats are installed back
m) Electrical components and music systems are reattached , and the dash is added back , winshields are added back sealed
Car then goes thru a fine detail process
Paint , color , rims
End result is a product 99.9% new and you can even add new digital parts in previously analog display systems
End product is a product with 7-10 years warranty as all components of the car are restored
So I hope that when our Railways say they overhauled a engine I hope they mean such , reconstruction of engine and not just buying a part from China and simple adding that in that is not overhaul its just repair work
This is a nice overhaul video
Japanese Consultants who Analysed Pakistan Railways Engineering stated
that Pakistani Engineers and Facility and workers are VERY hardworking and get thing done on time
However he noted that the are hindered by "Politics and No budget allocated for them to buy parts"
This study was done as part of Program by Japan to help construct the Rasulour factiry (Japanese donation) and they had also taught Pakistani engineers to build 1 Japanese Model (Licence)
This however did not improve Pakistan Railways to make new 10 Engines per years