Modernising Options

There are a wide range of “modernisation” modifications that can be applied to locomotives, both new and old.  The following table offers a quick guide to modernising options that might be adopted and the benefits that they offer.

Readers’ attention is also drawn to two extracts copied from David Wardale’s book:

The text and table below are taken from the 5AT website:



Increase Performance

Reduce Fuel Consumption

Reduce Maintenance


Improve Reliability

Improved exhaust system

Reduce backpressure in cylinders to increase cylinder efficiency & power output, & reduce specific steam consumption (SSC)

Fit Kordina below blast pipe

Reduce back-pressure in exhaust passages to increase cylinder efficiency & power output, & reduce specific steam consumption (SSC)

Convert firebox to GPCS operation

Reduction of: unburned fuel carry-over; smoke & spark emissions & clinkering;

Increase superheat temperature

Increase thermal efficiency, thus reducing SSC, fuel consuption and carbon emissions.

Install feedwater heater(s)

Reduction in SSC & fuel consumption and/or increase in steam production.

Cover all hot surfaces with high quality insulation

Minimise heat losses and reduce condensation on cylinder walls.

Improved valve and piston lubrication

Reduce piston and valve ring wear and cracking of lubricant oils by applying them directly onto rubbing surfaces.

Multiple narrow valve and piston rings

Minimise steam leakage; reduced ring wear.

Multiple element piston and valve rod glands

Eliminate steam leakage from glands between overhauls

Modify valve ports and valve heads

Improve streamlining to reduce triangular losses & improve cooling of valve liners, valve heads and valve rings

Saturated steam cooling of valve liners

Reduce liner temperature – recommended for very high temperature superheat

Increase steamchest volume and steam pipe diameter

Reduce pressure drop of admission steam at high steam flow rates, improving efficiency and SSC.

Optimise valve events

Improve steam flow into and out of cylinders by adjusting valve motion, lap and/or lead.

Optimise clearance volume by modifying pistons and/or cylinder covers

Raise SSC, efficiency, etc by reducing incomplete expansion losses without impeding steam flow.

Fit roller bearings wherever practicable

Minimise wear, knocking and loss of valve motion.

Fit Franklin wedges to hornguides

Postpone development of knocking as hornguides wear

Fit Franklin-type buffing mechanism between engine and tender

Reduce buffing shocks between engine and tender; reduce fore-aft rocking from unbalanced reciprocating masses

Fit air-sanding equipment

Reduce risk of slipping and consequent delays, damage etc

Adopt mid-gear drifting

Maintain steam pressure against admisssion edge valve rings, and prevent smokebox contaminants from entering cylinders.

Adopt Porta water treatment

Reduces or eliminates corrosion and scale formation; dramatically reduces boiler maintenance costs.