Signal Lever Force Indicator (SLFI)

Engineered in-house, the SLFI improves safety, by providing railway asset managers with the information they need to assess manually operated signal levers.

Excessive signal lever pull force often indicates that maintenance is required. The SLFI provides routine measurements that can be used as part of an ongoing maintenance regime to trigger targeted lubrication or component replacement.

Furthermore, high pull forces are a cause of back injury to signal operatives and, by identifying these situations early, the SLFI supports pre-defined safe operating levels.

These real-time force measurements can be used to develop energy efficient practices and form part of a training programme that demonstrates how force can vary according to the technique.


Download the data sheet

Features and benefits of SLFI:

  • Instantly measure pull force
  • Pre‐set warning lights for excessive load
  • Adaptable for different lever types
  • Use as part of an ongoing maintenance regime
  • Reduce likelihood of personal injury
  • Fully-calibrated across the working range
  • Easy to handle and transport
  • Battery powered and rugged design, supplied with heavy duty transport case

The SLFI is specially designed to measure the pull and push weight required to operate signal levers for points, FPL or signals. It displays peak load and indicates where pre-set limits have been exceeded.

The SLFI load frame attaches to the signal lever handle at the normal pull height, using a clamp on adapter, to ensure it is set at optimum height.

The SLFI pull handle connects to the load frame fitted with a full bridge strain gauge, featuring a digital display.

All SLFI units are calibrated prior to shipment on JF Strainstall's purpose-built test rig, designed to simulate actual loading conditions.

All load measurements are calibrated against weights certified using UKAS calibrated reference scales.

JF Strainstall recommends that SLFI equipment is re-calibrated annually.

SLFI system  

• Rugged design
• Large screen showing applied load
• Pre-set load indicators
• Tactile keys
• Quick start up and power down
• Low power with long battery life
• Rugged hard

 Screen  LCD display with LED backlight, digit size 20mm
 Keypad  Six-key silicon keypad
 Indicators  Pre-set 80Kg and 100Kg load indicator LEDs
 Display  Load / peak load hold
 Range  0—120Kg
 Accuracy  0.5% FS
 Power  DC 4.8‐24 VDC
 Battery  12V 2.5Ah NiMH
 Charging  Six hours (approx.)
 IP rating  IP65 nominally but is recommended for in-door use only
 Operating temperature  ‐5°C to +50°C
 Dimensions  H400mm x W90mm x D240mm
 Weight  4.35kg
 Calibration frequency  12 months