Key Takeaways
- A “train arrived” SMS dies at the intermodal ramp. The last-mile truck owns the consignee ETA — different SIM, different template.
- Slot A: terminal / yard PINs. Slot B: ramp overflow when the truck is offline — never rail promo.
- Free is 1 device, 300 SMS lifetime, and 300 contacts. Developer is 25,000 SMS per year. Platform price is devices plus send volume.
- Broker OTP stays on the warehouse chassis, not the ramp radio that already texted “on rail.”
- Idempotency is container-id plus leg (rail / truck) — not the consignee phone.
Summary
Scenario 471 is dual-SIM routing for rail-intermodal ramp-to-last-mile-truck handoff — not city slots, not air cargo, not van-to-bike, not ports as ocean terminals. The well car dies at the ramp. A drayage truck finishes the warehouse. Those legs must not share a default SIM or a single “your container arrived” lie. Service pricing is devices plus SMS send volume. You bring the phones and operator credit. Free is 1 device, 300 SMS lifetime, and 300 contacts.
Starter allows 2 devices: truck dual-SIM plus a spare ramp chassis. Uncapped platform volume is not unlimited carrier SMS. Confirm routing in Developer Center.
well car · ramp · truck PIN
one container-id, one public ETA at a time
Rail dwell is not the last-mile ETA
Ramp SMS ends at lift-off scan. Truck SMS starts after the drayage assign. Do not let the “train in” template keep firing while the box sits in the stack. Slot A on the warehouse phone owns PINs. Slot B is backup when the truck’s home operator dies under the crane.
If the rail-arrive event and the truck assign both fire “it’s here,” the warehouse opens the dock for a chassis still in the stack. Suppress ramp consignee templates the moment lift-off posts.
Intermodal dual-SIM matrix
| Leg | Radio | Failure |
|---|---|---|
| Rail / well | Ramp device, no PIN | Warehouse code sent from the stack |
| Lift-off | Suppress ramp ETA | Two “here” texts |
| Drayage assign | Slot A PIN / ETA | Promo SIM used at the gate |
| Crane no-reg | Slot B backup | OTP on the ramp radio |
Ramp-to-truck handoff
Persist container-id plus leg. Signed webhooks. Webhooks, DLR. MCP wraps REST only.
Terminal PIN and chassis
Hash, short TTL, warehouse slot A only. After OEM updates, canary both slots. UIC rail.
Devices, volume, and airtime
Two legs can double volume if you forget suppress. We meter devices and platform sends. Free (1/300/300) is one ramp proof.
Ramp operations
Charge both chassis, pairing, slot balances. Setup, Downloads, pricing.
Decision guide
Ship when rail ETAs die at lift-off. Delay if one SIM does both legs and promo. Not a CodeCanyon intermodal pack.
Intermodal checklist
- Leg-keyed idempotency.
- Ramp suppress on lift-off.
- PIN on warehouse slot A.
- Crane canary on slot B.
- Developer Center fields confirmed.
Next steps
Scenario 411 air cargo, scenario 351 bike hub.
Related product pages
Jump to the live product docs for this topic—not another long-form article.
- multi-device and dual SIM routingCapacity and failover
- transactional SMS for orders and alertsEvent-driven messages
- SMS delivery reports (DLR)Delivery status tracking
- SMS API documentationLive endpoint reference
