- hypothermia
- ice guard
- identification light
- igloo container
- hover pallet
- hovercraft
- hull
- hull insurance
- humidity measurement
- hump track
- ideal conditions
- idle time
- ice pack
- icebreaker
- ignitron locomotive
- impedance bond
- ignition generator
- ignition harness
- impact load
- impact stop
- impeller
- in ballast
- inbound heading
- index bar
- indicator lamp
- inflammable goods
- inflatable dinghy
- infrared detector
- indefinite term
- indicator
- individual control
- ingot
- ingot mold
- inherent availability
- initial advance
- incorporated
- index error
- indicator light
- industrial design
- inflow angle
- inflow ratio
- information bureau
- injection procedure
- injection pump
- inland haulage
- inlet
- inlet throat
- inner port
- instrument landing
- inshore pilotage
- instrument flight
- insufficient fund
- insulating fishplate
- interchangeability
- intercity train
- inland navigation
- inland waterway
- inner bottom
- inner skin
- innner ring
- inshore
- inshore pilot
- insolvency
- inspection cycle
- installment sale
- instrument flying
- insulated rail
- integrator amplifier
- interchange track
- interflow
- interior decorating
- interlocking limit
- intermodal traffic
- internal damping
- international currency
- international shopping
- international treaty
- international waters
- intersection
- intertuban train
- invalid
- invert
- irrigation structure
- inward-bound
- iron man
- island
- island depot
- jerry gang
- job master
- joint plate
- joint straightener
- joule
- jumper strut
- junction points
- jerry can
- jet stream
- jettison valve
- job description
- joint account
- jointless track