Project Overview
The State Railway of Thailand (SRT) operates multiple locomotive maintenance depots nationwide — Bangkok (Makkasan), Korat, Den Chai, and others — that required:
- Real-time monitoring of heavy machinery (overhead cranes, hydraulic presses, wheel lathes)
- Predictive maintenance signatures from vibration + temperature analysis
- Remote dashboard accessible from HQ + locomotive depots
- Cyber security — government work requires isolation from enterprise network + complete audit trail
Sahawatthanakit (1988) delivered a full turnkey EPC scope — survey, system design, equipment supply, installation, commissioning, and 1-year support.
Design Methodology
Step 1 — Site Survey + Asset Audit
- Critical asset identification — 32 assets per depot (cranes, presses, lathes, compressors, transformers)
- Vibration + temperature baseline signatures measured per machine
- Existing network infrastructure survey — most were isolated control LANs (no internet connectivity)
- Power audit — load + harmonic profile on main panels
Step 2 — System Architecture
[Sensor Layer]
├─ Vibration accelerometer (ISO 10816 mounted)
├─ PT-100 RTD temperature
├─ Current transformer (CT) clamp-on
└─ Ambient temp/humidity DHT22
│
▼
[Edge Gateway Layer]
├─ PLC (Siemens S7-1200 / Mitsubishi Q-series)
├─ I/O module 16AI/16DI/8AO
└─ Edge compute (Beckhoff CX) for FFT analysis
│
▼
[Communication Layer]
├─ NB-IoT cellular (no fiber needed → fast installation)
├─ MQTT broker (Mosquitto) on-premise
└─ VPN tunnel back to SRT enterprise DMZ
│
▼
[Application Layer]
├─ SCADA — Ignition / Wonderware
├─ Time-series DB — InfluxDB / TimescaleDB
└─ Dashboard — Grafana + LINE alert
Step 3 — Engineering Calculations
- Sensor sampling rate — vibration 25.6 kHz (Nyquist >10 kHz signature)
- FFT window — 4-second Hanning window, 50% overlap
- Alert thresholds — ISO 10816-3 Zone B/C/D boundaries per machine class
- Network bandwidth — sized for 30-day historian + 8 sensors × 10 Hz per gateway
Installation
| Parameter | Specification |
|---|---|
| Sensor count | 120+ (vibration 48, RTD 36, CT 24, ambient 12) |
| PLC / Edge gateway | 8 cabinets — IP54 enclosure, DIN-rail mount |
| Power | 220 VAC UPS-backed (30-minute runtime) |
| Network | NB-IoT (AIS / dtac) + LoRaWAN backup |
| SCADA HMI | 3 displays — depot + maintenance office + HQ |
| Cyber security | VPN-tunneled MQTT, RBAC 4 roles, 90-day audit log |
| Commissioning | FAT (factory acceptance) + SAT (site acceptance) per IEC 62381 |
| Installation duration | 12 weeks per depot |
| Training | 16 hours for SRT engineers — SCADA + dashboard + alert tuning |
| Warranty | 1 year + 24/7 remote support |
Results (18-month accumulated data)
| Metric | Outcome |
|---|---|
| Critical assets monitored | 120+ across 3 depots |
| Unplanned downtime reduction | ~22% vs pre-installation baseline |
| Predictive alerts triggered | 47 total · 39 true positive (83%) |
| Detected before failure | 31 cases (66%) — maintenance scheduled before failure |
| Network uptime | 99.6% (NB-IoT + LoRa backup) |
| Cyber audit | Passed SRT internal IT audit + ISO/IEC 27001 baseline review |
| User adoption | 12 engineers using dashboard daily post-training |
Why SRT Chose Us
- Full EPC scope — survey + design + supply + install + commissioning + support — no multi-vendor coordination
- Standards-complete — IEC 61131-3, IEC 61850, IEC 62443, ISO 27001 — government work requires full documentation per phase
- NB-IoT = fast install, no cable trenching — older depots had no ethernet trough; cellular IoT solved this
- Predictive analytics, not just data collection — FFT + threshold tuning + alert routing
- Government-grade cyber security — VPN + RBAC + audit log + enterprise LAN isolation
- Training + 24/7 remote support — SRT engineers operate independently post-training; we backstop for major issues
- Established SRT vendor relationship — 8+ years prior in lubricant supply gave us procurement-process familiarity
Related Services
Looking for IoT + Electrical Engineering + SCADA systems for factories, state enterprises, or critical infrastructure? Our engineering team can survey + design system architecture + quote turnkey EPC.
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