Mallet locomotive

Combined membership test

Record evidence for both the frame relationship and staged steam expansion before assigning strict Mallet membership.

1. Which drawings or inspection observations establish the fixed rear engine and pivoting front engine? definition
2. Does the documented normal steam circuit connect rear high-pressure exhaust to front low-pressure admission? boundary

Name versus machinery

Associate each classification with a dated configuration and distinguish original equipment from conversion.

1. Which builder, railway or museum records establish the original configuration and later conversions? provenance
2. If a source calls a simple-expansion locomotive a Mallet, is that historical naming or a broader architectural usage? boundary

Support arrangement

Record the actual support arrangement; the conventional fixed-rear and sliding-front arrangement must not erase documented variants. [Baldwin technical account](https://www.catskillarchive.com/rrextra/blwmal00.Html)

1. Where are the articulation pivot and boiler supports, and which movements does each permit? definition
2. What measured pivot and support clearances apply, and which maintenance document supplies their limits? measurement

Route-fit evidence

Require configuration-specific geometry and axle-load evidence before judging route compatibility.

1. What minimum curve radius, front-engine sweep and clearance envelope are documented for this configuration? measurement
2. Do the proposed route's gauge, curvature, clearances and axle-load limits accommodate the locomotive in its intended loading condition? action

Receiver and moving connections

Identify the receiver and flexible steam or exhaust connections, including their accommodation of movement and thermal expansion. [Baldwin technical account](https://www.catskillarchive.com/rrextra/blwmal00.Html)

1. Which pipes and joints connect the expansion stages and exhaust, and how does each accommodate articulation? definition
2. What pressure, leakage and movement observations establish the condition of these connections? measurement

Documented mode transitions

Record starting provisions, reversing arrangements and cutoff control from the applicable design documentation.

1. What starting or intercepting arrangement is fitted, if any, and how does its steam path differ from normal compound running? definition
2. Which approved checks establish correct mode transition and valve-control movement throughout the permitted articulation range? action

Documented duty envelope

Record configuration-specific hauling evidence, adhesion assumptions and supply requirements.

1. What measured or documented tractive effort and sustained speed apply to the proposed load and gradient? measurement
2. What fuel, water and lubrication provisions support both engine units for that duty? action

Articulated machinery readiness

Link pivot wear, support condition, pipe leakage, linkage interference and running-gear defects to documented disposition.

1. Which inspections establish the condition of the articulation, moving pipes, control linkages and both engine units? provenance
2. Which recorded defects require repair, restricted movement or withdrawal under the applicable maintenance instructions? action

Action-specific authorisation

Distinguish static display, cold movement, steaming and hauling using linked boiler, brake and operational evidence.

1. Which authority and current rule edition govern the proposed activity, and what inspection or certification evidence is required? provenance
2. What fitted protective devices, operating procedures and restrictions must be verified before that activity? action

Check these first

Recalled without web access and unsourced; every item is a lead to verify.

1. Which of these check these first hold for the sense of Mallet locomotive this model covers, and on what evidence? provenance

Kinds and varieties

Recalled without web access and unsourced; every item is a lead to verify.

1. Which of these kinds and varieties hold for the sense of Mallet locomotive this model covers, and on what evidence? provenance

Identifiers and schemes

Recalled without web access and unsourced; every item is a lead to verify.

1. Which of these identifiers and schemes hold for the sense of Mallet locomotive this model covers, and on what evidence? provenance

Real-world use

Recalled without web access and unsourced; every item is a lead to verify.

1. Which of these real-world use hold for the sense of Mallet locomotive this model covers, and on what evidence? provenance

Failure modes and hazards

Recalled without web access and unsourced; every item is a lead to verify.

1. Which of these failure modes and hazards hold for the sense of Mallet locomotive this model covers, and on what evidence? provenance

Regional variation

Recalled without web access and unsourced; every item is a lead to verify.

1. Which of these regional variation hold for the sense of Mallet locomotive this model covers, and on what evidence? provenance

Neighbouring kinds and how to tell them apart

Recalled without web access and unsourced; every item is a lead to verify.

1. Which of these neighbouring kinds and how to tell them apart hold for the sense of Mallet locomotive this model covers, and on what evidence? provenance